GIA Colored Stones Practice Test

These questions are part of the practice quiz. Start practicing

• What is a doublet in gemstone terminology?
• The color of Australian blue sapphire is often described in what way?
• What inclusions are notably found in pyrope, spessartine, and almandine garnets?
• Which country is known for the production of most of the world's commercial-quality peridot?
• What aspect of gem treatment does not involve cutting or polishing?
• What does the term 'precious topaz' refer to?
• Which of the following is classified as a gem treatment?
• Which characteristic is NOT associated with rutilated quartz?
• What are centipedes in the context of moonstone?
• What is the purpose of fracture filling in gemstones?
• What does "eye clean" mean when describing a gemstone?
• What does "color range" refer to in gemology?
• Which geographical source is NOT known for producing sapphires?
• What does extinction in a gemstone result from?
• What is reconstructed turquoise primarily made from?
• What is a lot price in the context of gem purchasing?
• What is a key characteristic of gems found in eluvial deposits?
• Which trace elements cause the blue color in corundum?
• Type C jadeite is identified by which characteristics?
• What is the purpose of a certificate of origin for gemstones?
• What does the term "aggregate" refer to in gemology?
• Blue sapphire's pleochroic colors typically include which of the following?
• How deep is the color layer created by lattice-diffusion with titanium or chromium in corundum?
• What mineral content is primarily responsible for the vibrant blue color in turquoise?
• What characterizes a cryptocystalline structure?
• What tone levels of the GIA Colored Stone Grading System apply to grading transparent colored stones?
• When evaluating opals, what aspect should be considered as separate from its play-of-color?
• What is the main attribute of Type A jadeite?
• What does a memo in the context of gemstone dealing refer to?
• What characterizes potch opal?
• Which term describes a random sample taken from a parcel of gemstones to assess overall quality?
• Which cutting style combines brilliant-cut and step cut facets?
• In which era did moonstone lose its popularity?
• What is the most common use for coral in jewelry making?
• What term is often used to indicate multiple individual stones sold together?
• What does the term 'window' refer to in the context of transparent gemstones?
• What does lattice diffusion refer to in gem treatment?
• In jadeite classification, what does Type C refer to?
• What is the term for the price associated with buying an entire parcel of gems or a substantial part of it?
• What types of elements are pegmatite gems typically rich in?
• What is a geode?
• Which region is known for producing jet?
• What is the primary coloring agent for Tsavorite garnet?
• What causes the color in many blue sapphires through intervalence charge transfer?
• Which factor influences the value of turquoise in gemstones?
• What phenomenon describes the substitution of one chemical element for another in a mineral's crystal structure?
• Which type of cut usually leads to a gemstone having less brilliance?
• What is the primary color range of jet as a gemstone?
• What effect does heat treatment in a reducing environment have on sapphire?
• What is 'quench cracking'?
• What is a major source of black star sapphire?
• What describes the premium price for selecting stones from a parcel?
• What role do transition elements play in gemstones?
• Which fancy sapphire hue is known for commanding top prices?
• What is milky, grayish, or brownish corundum that can be treated to a fine blue color known as?
• Newly discovered ruby deposits at Vatomandry and Andilamena are found in which country?
• Which type of turquoise is known for having web-like matrix patterns?
• Where were trapiche emeralds first discovered?
• Which of the following is produced by a pearl-bearing mollusk?
• Watermelon tourmaline is characterized by which specific color zoning?
• Why are round pearls generally more valuable than other shapes?
• Which term refers to a pearl formed through natural processes?
• Which gemstone characteristic involves the geographical location of mining?
• Which characteristic best describes the structure of feldspar?
• What term describes a group of pearls that have minor variations in uniformity?
• Which animal's tusk is known for producing the most valuable ivory?
• What is a triplet in gemstone terminology?
• What characteristic is NOT associated with an amorphous gemstone?
• What gives jadeite its finest green color?
• What is described in the solution process for growing synthetic crystals?
• Which mineral is classified in the orthorhombic crystal system?
• Which gem is capable of displaying three pleochroic colors?
• What element is primarily responsible for the color changes in sapphire?
• What characteristic does 'relief' provide in terms of gemstone inclusions?
• What is the name of quartz or topaz that has a thin layer of gold deposited on its surface?
• What property defines igneous rocks?
• When was the Sandawana emerald mine discovered?
• What part of a gemstone is referred to as the crown?
• What is the role of weak atomic bonds in gemstone cleavage?
• Which of the following is a characteristic of gemstones with deep pavilions?
• Which topaz varieties are considered the most valuable?
• What does fluorescence in gemstones refer to?
• What trade term is used for blue tourmaline?
• What process involves heating finely ground powder under pressure?
• Which property affects a gemstone's color through visible light absorption?
• What is a characteristic or irregularity confined to the surface of a polished gemstone known as?
• How are individual stone prices generally referred to?
• What characterizes a circled pearl?
• What phenomenon does pleochroism refer to?
• What feature makes ivory especially valuable in craftsmanship?
• Which elements are responsible for the intense red color of spinel?
• How is dark amethyst typically lightened?
• What is defined as 'unit price' in gemstone valuation?
• Most of the citrine available in the market is produced from which process?
• What is tourmalinated quartz?
• Igneous rock is formed through which process?
• What does heat and pressure transform limestone into?
• In terms of market demand, which option is most indicative of ruby prices?
• What is indicated by the term 'hollow cavity' in gemstone context?
• Which characteristics do the most valuable topaz varieties typically possess?
• Which industry directly contributed to the decline of the natural pearl industry?
• What kind of items are typically found in the high-end market for gemstones?
• What is a broad gem category based on chemical composition and crystal structure called?
• What term describes minerals dense enough to be separated from lighter ones by surface water action?
• What term is used to describe the theft of gemstones or production by workers from a mine?
• What is a mantle-tissue piece used for in gem production?
• What are the four major sources of emeralds?
• What is Moldavite primarily classified as?
• Which term best describes a gemstone that has inclusions visible from its surface?
• What does 'placer' refer to regarding gem deposits?
• What element colors Paraiba tourmaline?
• What defines a cultured pearl?
• What treatment can create a golden color for black coral?
• How is benitoite primarily distinguished from other gemstones?
• How do emeralds from African mines compare to those from other sources?
• Which of the following is a characteristic of Type A jadeite?
• Moonstone is a variety of which mineral?
• Which type of aggregate's crystals are visible only with magnification greater than a standard gemological microscope's?
• How are many green and blue tourmalines lightened?
• What is a 'strand' in the context of pearls?
• What does the "flame fusion" process create?
• What is the finest trade grade of lapis lazuli?
• What is the highest clarity grade for colored stones?
• What is a polymer in relation to gemology?
• Which type of cultured pearl is primarily cultivated using a bead nucleus?
• What does piezoelectricity in crystals cause them to do?
• What is nacre?
• What is the weight equivalence of one metric carat?
• What is the primary condition that leads to unintended color zoning in gemstones?
• Which process is often employed to grow synthetic gemstones in large volumes?
• What is Goldstone primarily made of?
• What describes the carving style known as cameo?
• What is the most common crystal habit of blue sapphire?
• In which country are the Penny Lane and John Saul mines located?
• What is notable about a step cut gemstone?
• What does the term "habit" refer to in mineralogy?
• An angular, hollow space that resembles a mineral inclusion is referred to as a:
• What process involves exposing a gem to rising temperature to change its appearance?
• What type of lighting is considered best for grading color in a colored stone?
• What does aventurescence refer to?
• What feldspar is greenish blue with gridlike white streaks, resembling turquoise?
• What are the most valuable tone and saturation characteristics for ruby?
• What is the primary role of a wholesaler in the gem and jewelry industry?
• In which decade did Madagascar become a significant source of blue sapphires?
• What does growth zoning in a colored stone indicate?
• Which process leads to the creation of synthetic crystals through melted materials?
• What does 'style' refer to when discussing a gemstone's facets?
• What are 'proportions' in relation to polished gems?
• What occurs during the geological process of subduction?
• What type of tourmalines are most commonly found in the gem market?
• What is the purpose of the sugar treatment in opal processing?
• What is a Slocum stone?
• Why is position important in determining the value of a gem?
• What is polar jade primarily classified as?
• In mineralogy, what does the term 'crystal structure' refer to?
• Which color of amber is generally considered the most valuable?
• What is the term for the broad color flash seen in certain gems?
• Which location is known as the most important source of aquamarine?
• Which material do rubies from marble deposits typically have low levels of?
• What is meant by the 'high-end market' in gemstones?
• Where do Vietnamese rubies originate from?
• What does saturation refer to in terms of color?
• What defines a silicate mineral?
• What type of gemstone is created by fusing two materials together?
• In which country do most gem-quality tourmalines form?
• Which colored stone type typically includes inclusions that do not significantly impact clarity?
• What is a characteristic feature of synthetic opal?
• What does chemical composition refer to in gemstones?
• Which location is known for producing the majority of rubies that are used in mass-produced jewelry?
• What is chalcedony with curved or angular bands or layers that differ in color and transparency called?
• What color is spinach jade primarily associated with?
• What characterizes metamorphic rock?
• What term is used for a cylindrical synthetic crystal produced by the flame-fusion process?
• What is a common treatment for enhancing the appearance of gemstones like amethyst?
• Which term describes molten rock beneath the Earth's surface?
• Which gem is frequently subjected to heat treatment?
• How is a specific quality range of rough gemstones determined?
• In what context is "orient" specifically important for pearl quality?
• Corundum requires what type of environment to form?
• Which trade term describes certain tourmalines known for their vivid colors?
• Which two countries account for approximately 75 percent of emerald purchases worldwide?
• What is the main feature of a brilliant cut?
• What is meant by the term "alluvial deposit" in geology?
• What is a common reason for rubies being fashioned with shallow proportions?
• Which garnet variety is known for its dark red color?
• Which cutting stage has the greatest impact on the final value of the gemstone?
• Which lapis lazuli trade grade is characterized by green spots and noticeable calcite?
• What classification is described as "Nucleus not noticeable, no chalky appearance"?
• In what decade were emeralds discovered in Zambia?
• What type of inclusion is generally accepted in Type I clarity gems?
• What does "orient" refer to in relation to certain gemstones?
• What does the term 'gem enhancement' refer to?
• Which country is known for producing the most freshwater cultured pearls?
• Which process is most likely used to produce synthetic turquoise?
• What is the international unit of measurement for gem weight?
• What does "cloud" indicate about a gemstone's quality?
• What is the definition of a mineral?
• What are 'value factors' when discussing pearls?
• What began to happen to oysters in many important Japanese cultured pearl farming areas in the early 1990s?
• Which gemstone is often treated with heat and sugar for enhancement?
• What is the primary purpose of sawing in gemology?
• What does the term "intaglio" refer to in gemstone processing?
• What is the trade term for the vivid blue adularescence displayed by high-quality moonstone?
• What does the term 'source' refer to in the context of gemstones?
• What effect does heat-treating have on Mong Hsu rubies?
• What changes during the alexandrite color-change effect?
• Compared to rubies from Myanmar, rubies from Thailand tend to be:
• How is the grade of a gemstone determined?
• Which country is known as a significant source of fine sapphires over 100cts.?
• Which statement best describes a wholesaler's function in the jewelry market?
• What color is chrysoprase typically?
• For the flux growth method, which material is ideally used for crucibles?
• What is a signet gem typically associated with?
• What characterizes labradorescence?
• What is the background color of an opal?
• What defines a fracture in gemology?
• What does the term "feather" signify in gemstones?
• What is a cabochon?
• What is the process of removing heavily included sections from gemstone rough by tapping with a small hammer called?
• What is the major source of turquoise today?
• Which property makes Moldavite highly sought after?
• What is the term used for a gem's price divided by its carat weight?
• In what type of geological formation is the majority of gem-quality topaz found?
• In terms of star sapphire, what does asterism refer to?
• Which of the following is widely recognized as the most valuable chatoyant gem?
• What is meant by 'custom-made jewelry'?
• How is durability defined in the context of gemstones?
• What is the process called that leads to localized changes in rock due to igneous intrusion?
• What defines planned light leakage in gemology?
• What is agate primarily composed of?
• Which gem is classified as Type III?
• What process typically involves manipulating the molecular structure of gemstone settings?
• What defines a 'primary deposit' of gems?
• What three basic chemical elements are contained in all feldspars?
• What is a potential consequence of the oyster die-off in cultured pearl farming?
• Which of the following is an example of an organic gem?
• What defines the middle market in gemstone jewelry?
• What is opaque or translucent rough often shaped into?
• Amber is primarily derived from what type of natural material?
• What is the significance of the term 'window' when discussing gemstone clarity?
• What is the primary component of opal?
• What are the two common types of inclusions found within gemstones?
• What does the term 'pavilion' refer to in the context of faceted gems?
• What element provides the color in Rubellite tourmaline?
• Which agent can create a shallow layer of asterism in a corundum cabochon?
• What is the primary use of flux growth in gemstone creation?
• What term describes a mineral deposit that occupies an existing fissure in rock?
• What is the term for workable alluvial deposits of gem materials with economic potential?
• New Zealand is known as a major source of which type of jade?
• How is chalcedony different from agate?
• Which type of crystal property involves the ability to generate an electric charge?
• Why is rarity considered an important factor in determining whether a mineral is a gem?
• What type of gemstone would you classify as an imitation gem?
• What phenomenon causes the cloudy bluish white light observed in moonstone?
• What generally influences the pricing of pink sapphires?
• Which gem is known for its chatoyancy caused by multiple slender crystals or channels?
• What is the finest texture category of jadeite known as?
• Which type of turquoise is usually more desirable?
• Color-change sapphires typically shift from blue to violet and then to which color?
• What characteristic is NOT typically associated with minerals?
• What term describes spots of color near the surface of a jadeite boulder?
• In gemology, what is the significance of a commercial market?
• What treatments are commonly applied to jadeite?
• What color variations can topaz naturally exhibit?
• What is the market level supplied by Switzerland for sapphires?
• What are "fingerprints" in the context of gemstones?
• What type of color is associated with the mineral hiddenite?
• A number of similar cultured pearl strands bundled together is referred to as a what?
• In the nineteenth century, a major source of amethyst was discovered in which country?
• Asterism in star sapphire is caused by which mineral?
• If a crystal grows in a flux that is highly saturated with the necessary elements, the resulting crystals are likely to be:
• Heat treatment of jadeite can produce which color?
• In which type of rock are gems formed from pegmatite typically found?
• What is the primary definition of a gem?
• Who produced a hydrothermal synthetic emerald layer over faceted beryl seeds in the 1960s?
• What does the term 'adularescence' refer to?
• What is the significance of the term "precious" when referring to specific types of topaz?
• How does a window typically differ from the rest of the stone?
• In the context of gemstone production, what does 'pulling' refer to?
• What defines the process of precipitation in gem synthesis?
• What term is used for yellow-to-orange stones of topaz?
• Which mineral family does garnet belong to?
• What are the needles of actinolite found in emerald classified as?
• To accurately judge the brilliance of a gemstone, one should view it:
• The color of amethyst results from what acting on iron?
• Type A jadeite is characterized by which of the following?
• Plastic imitation opal was first marketed in which country?
• What does the crown-height to pavilion-depth ratio indicate?
• What is "Paua" in Maori?
• What is the most valuable color of coral?
• What is the primary use of specific gravity in gemology?
• What does twinning refer to in gemology?
• What is the definition of the term 'crust' in geology?
• What does a 'cutting center' refer to?
• What remains of the ancient plant matter in lignite coal primarily composed of?
• Where was jadeite first fashioned for use as an ornamental object?
• What is the transparency level of gray-base black opal?
• What is the oyster species used to grow Tahitian cultured pearls?
• What type of twinning occurs due to environmental changes after the gem has formed?
• Which of the following describes a solid crystal inclusion?
• What is a mabe in terms of pearl formation?
• What feature distinguishes demantoid from other garnets?
• What term describes the presence of impurities, such as trace elements, within a gemstone?
• Who is a 'cutter' in the jewelry industry?
• What are areas of lower color intensity in colored stones cut flat with shallow pavilions called?
• What is a common characteristic of ceramic-processed gems?
• Which of the following best describes the brilliance of a gemstone?
• What defines a synthetic gem?
• Which element is responsible for giving ruby its red color?
• How is a metamict mineral defined?
• What defines a chemical element in the context of gemstones?
• What characterizes a "fantasy cut" gemstone?
• Which two minerals are known to be cryptocrystalline aggregates besides turquoise?
• Which of the following processes does NOT lead to the formation of metamorphic rocks?
• What is the natural source of ametrine?
• What technique do cutters use to retain as much weight as possible from rare, high-quality rough?
• What is Essence d'orient made from?
• What is the most important gem export of Myanmar?
• What color marking is created by the sandstone matrix in turquoise?
• Which property of opal can vary significantly among different specimens?
• Spinach jade refers to a color associated with which mineral?
• Blue zircon typically has a color known as?
• Which of the following is an effect commonly seen in gemstones like sunstone?
• What is the name of the pattern in opal characterized by large, distinct, rectangular patches of play-of-color?
• What term is used for atoms in a gem that are not part of its essential chemical composition?
• What crystal growth habit can be compared to a cluster of grapes?
• Most colored stones are sold by which measurement?
• What causes the purest blue colors of turquoise?
• What describes a crystal growth habit characterized by a bumpy appearance?
• Which term describes a family of gems from several closely related mineral species?
• What does the term "amorphous" describe in the context of gemstones?
• What characterizes a liquid inclusion within a gem?
• What is the name of the largest gem-quality natural pearl known?
• What is the background color of semi-black opal?
• What is the chemical component that provides the color for Demantoid garnet?
• Which type of rough gemstone is typically faceted?
• What defines a three-quarter-cut in gemstones?
• Saltwater whole cultured pearls grow from a piece of what?
• What does selective absorption refer to in gemology?
• Which jadeite type typically exhibits the highest level of value and quality?
• What is a quantity of stones, sometimes of similar size and quality, from a single mine or various sources called?
• How does high grading affect a mining operation?
• In the early 1980s, which country was the major source for rubies?
• What term describes the contrast between an inclusion and its host gem?
• What are trace elements in gemstones?
• Which type of cultured pearls are almost always bleached?
• By what year had Kokichi Mikimoto begun culturing whole pearls?
• What is the primary structure of all garnets?
• Which of the following describes an igneous rock?
• What is thought to cause the background color of fire opal?
• What process can create an intense, unstable green color in spodumene?
• What is the characteristic feature of "Maraba" amethyst?
• Which mineral is commonly used as a color component for malachite?
• What is the main purpose of bleaching in gemstone treatment?
• What does pneumatolysis involve?
• What does irradiation do to a gemstone?
• What is "essence d'orient" used to create?
• What does 'stabilized turquoise' refer to?
• What type of material is chalcedony classified as?
• Which type of treatment is often associated with enhancing the color of sapphires?
• What effect does excessive bulge on a step cut have on the gemstone?
• Which characteristic defines the best-quality star corundum?
• Which category of gems includes aquamarine and yellow beryl as typically eye-clean?
• What type of pearls are rice pearls specifically categorized under?
• Which of the following best describes the appearance of trace elements?
• What characterizes a reducing environment surrounding a gem during heat treatment?
• What category of colored stone is typically sold per piece?
• The measurement of a colored gemstone's depth can primarily affect which grading factor?
• Which treatment is primarily used to change light-colored spodumene to kunzite?
• What is a mineral?
• What is a deposit called where gems are found in the rock that carried them to Earth’s surface?
• What characterizes a three-phase inclusion in a gem?
• What does the term 'volcanic' refer to in geological contexts?
• How is the term 'stability' defined in relation to gemstones?
• Which clarity type typically features gems that are usually eye-clean?
• What does the phenomenon refer to in gemology?
• In synthetic crystal growth, what does the flux growth process primarily involve?
• What is a notable physical property of Kashmir sapphires?
• What is the common term for the brilliant colors exhibited by opal when viewed from different angles?
• The hydrothermal synthetic process requires which of the following?
• What region is the world's largest producer of gem-quality tourmaline?
• What does 'unplanned light leakage' imply about a gemstone?
• What is a gem species based on?
• Emeralds primarily form under which geological conditions?
• Who created the first marketable synthetic opal?
• What type of crystal structure does rough spinal often exhibit?
• What qualifies a gem as a natural gem?
• What is the finest-quality jadeite referred to as?
• What is the most important recent source of rhodolite garnet?
• What term describes rough that has been ground to the approximate shape of the finished stone?
• What method is primarily used to produce synthetic aquamarine?
• Which country is the largest producer of chrome tourmaline?
• Which element is responsible for the red color in ruby and the green color in emerald?
• When discussing colored gemstones, what is meant by "color zoning"?
• In what type of environment does turquoise typically form?
• Which type of beryl is considered the rarest?
• What is the trade name for pink to red elbaite tourmaline?
• Which term describes a fracture pattern that creates curved and ridged surfaces in a gemstone?
• Pearls that exhibit noticeable surface characteristics are classified as what?
• What does bleaching involve in gemstone treatment?
• What process does grinding involve in gemstone preparation?
• Unintended color zoning in gemstones refers to?
• What is a defining feature of said glicosope?
• Which of these is a cutting center for colored stones in Thailand?
• Which of the following is classified as an amorphous gem?
• What characterizes a graduated strand necklace?
• In pearl grading, what signifies a 'poor' rating?
• Which gem is known for its ability to exhibit play-of-color?
• What does the trade term "Zambian" refer to in emeralds?
• What is the most common treatment for light-colored spodumene to achieve a kunzite color?
• What are secondary deposits of gems?
• What is the main effect of colorless impregnation on a gemstone's appearance?
• What is the focus of plate tectonics?
• What trade name has been commonly used for Mandarin garnet?
• In a parcel of amethysts weighing 1,542.00 carats with a cost of $0.75 per carat, what is the unit price if it contains 1,000 stones?
• Rocks that have been altered by heat and pressure are called what?
• What color is top-quality alexandrite in daylight?
• Where were the first black opals discovered?
• What causes iridescence in gemstones?
• What characterizes designer cuts in gemstones?
• What does the term "mine lot" or "mine run" refer to?
• Which of the following describes the chemical composition of gem species?
• Which country is known as the only commercial source of charoite?
• Which two elements are primarily responsible for color change in gemstones?
• What does 'silk' refer to in gemstones?
• What percentage of water does most opal contain?
• What does brilliance refer to in the context of gemstones?
• Emeralds are rarely found in placer deposits because they are:
• Which natural element is a common inclusion in emeralds?
• How is a cultured blister pearl formed?
• Which type of deposit is typically the most profitable for colored stone mining?
• What is the definition of inorganic in relation to matter?
• Which of the following best describes the term 'inclusions' in gemstones?
• What tonal quality do fancy sapphires from Montana typically exhibit?
• What is meant by 'unit cell' in mineralogy?
• What is a hololith in gemstone jewelry?
• Which type of gem is described as idiochromatic?
• What gemstone characteristic provides information on how light interacts with it?
• What type of gem is a pearl classified as?
• What is the definition of a cavity in gemstone terminology?
• What is the estimated percentage of fashioned emeralds that contain filled fractures?
• What does mottling describe in the context of gemstones?
• What does the term calibrated sizes refer to?
• What defines two-phase inclusion in a gemstone?
• What is the purpose of the "faceting head" in gemstone processing?
• What is meant by “hydrothermal fluid”?
• Imperial Topaz is known for which coloration?
• What is the trade term for a vibrant green tourmaline colored by traces of vanadium or chromium?
• Which of the following does NOT describe sedimentary rock?
• What is the purpose of a hardener in resin application?
• Which type of gem is derived from a living organism?
• Which best describes a mineral?
• What is a sorting pad primarily used for in the gemstone industry?
• What is the role of conchiolin in nacre?
• What is the cost of a ruby that weighs 5.76 carats with a per-carat price of $5,500.00?
• What is spontaneous nucleation in terms of synthetic crystal growth?
• Which of the following best describes the formation process of rocks involved in regional metamorphism?
• Which oyster is commonly associated with the production of Akoya pearls?
• What phenomenon describes play-of-color seen only when light travels through an opal to the eye?
• What is a common metal found in many Paraiba tourmalines?
• What is a chip in the context of gemstones?
• What does "origin" indicate when discussing gemstones?
• What is the name of one of Colombia's traditional emerald mines?
• What can cause adularescence in a gemstone?
• What does the term “hue” refer to in the context of colored stones?
• Which garnet variety is specifically known for its green color?
• What does "assembled stone" refer to?
• What is cleave in gemology?
• Which overtone color is known to enhance the value of akoya cultured pearls with a white bodycolor?
• What is the characteristic color of malachite?
• What is the primary function of a lap horizontal in gem processing?
• In gemstone grading, what is a critical factor affecting value?
• Which color of star sapphire is typically shallow due to parting?
• What does the term "double refraction" refer to?
• What aspect of gem mining often involves independent workers?
• Which of the following is true about the color of chrome diopside?
• The term "black onyx" is often used for which type of stone?
• What is one of amethyst's finest colors?
• What is the term used for the process where turquoise is artificially created?
• Where is the only source of red beryl located?
• Where is an inclusion with the most negative impact on a colored stone's clarity typically located?
• Which phenomenon is described as diffraction?
• Which variety of tourmaline is known to be the most expensive?
• Which substance is used to fill fractures in gemstones?
• What is jet primarily composed of?
• What is meant by free-size cutting in gemstones?
• Which element is responsible for the color in both almandine and peridot?
• In ancient Sanskrit, what is the ruby referred to as?
• Which trace elements are responsible for the color of blue sapphire?
• What color is considered the most valuable for spinel?
• What does a consignment mean in the gemstone trade?
• What is a bead nucleus?
• What is the purpose of a sieve set in gemology?
• Which unit is primarily used in the gem industry for measuring weight?
• In the context of colored gemstones, saturation refers to what?
• What is described as a number of cultured pearl strands bundled together?
• Which type of tourmaline is known for its rarity and vibrant colors?
• What are fingerprints in gems?
• What is a pearl primarily formed from?
• Guatemala is a valuable source of which jadeite color?
• Which gem is considered the most-prized chatoyant gem in the world?
• What does the term 'process' refer to in cultured pearl preparation?
• A colored stone that rates "fair" for brilliance has what percentage of brilliance?
• What does the term "parti-colored" refer to in gemstones?
• What does smoke treatment do to an opal?
• What term describes a gemstone cut that has a flat face?
• When grading a colored stone, which factor does NOT directly influence its hue?
• What term is used for the vibrant green to blue or violet elbaite tourmaline originally found in Brazil?
• Which garnet variety is often used as a substitute for diamonds due to its brilliance?
• Which country is the major source of commercial-quality amethyst?
• What is the core of the Earth?
• What does the name "padparadscha" translate to in English?
• For clarity enhancement, the material used to fill a gem's fractures must have what property?
• What term refers to the pattern shown by certain gems when viewed through a spectroscope?
• What is the main cause of regional metamorphism in rocks?
• Which term best describes a natural material made up of a mass of one or more kinds of mineral crystals?
• Which of the following describes surface characteristics in pearls?
• What is 'reconstructed turquoise' made from?
• What does the term "allochromatic" refer to?
• What does the girdle of a gemstone refer to?
• What is referred to as a uniform strand?
• Which location is known for supplying sapphires that are most likely not heat-treated?
• What is mantle convection responsible for?
• What is asterism in gemstones?
• Which type of coral is particularly sought after for its color and rarity?
• South Sea cultured pearls are principally produced in which countries?
• What color is characteristic of morganite beryl?
• What causes the pink color of corundum?
• How is the color of an idiochromatic gem determined?
• Most gemstones form in which part of the Earth's structure?
• What characterizes a natural pearl?
• What mineral is known as the world's major source of lapis lazuli?
• What does surface modification involve?
• What type of sedimentary rock is lignite coal?
• Where is the only source of gem-quality benitoite located?
• What kind of gemstones are commonly found in secondary deposits?
• What is the major source for top-color turquoise today?
• What type of gem can show pleochroism?
• What distinguishes Type B jadeite from other types?
• What defines an imitation gem?
• What causes color zoning in a gemstone?
• During which years did Kashmir primarily produce sapphires?
• What defines an eluvial deposit?
• What does charge transfer in gemstones refer to?
• What characterizes spiderweb turquoise?
• What is the market sector for better-quality gemstones used in well-finished, moderately priced jewelry called?
• Generally, cool-colored hues with low saturation appear to be?
• To which group does almandine belong?
• What is the major source of imperial topaz?
• What is the adularescence of the finest moonstone characterized by?
• In which type of stone is creating asterism with heat treatment most commonly applied?
• Which mineral type do tsavorite and hessonite belong to?
• What is the purpose of a matching tray in gemstone evaluation?
• Which mineral inclusion is known to enhance the star effect in star sapphires?
• Which abbreviation does the GIA Colored Stone Grading System use for a slightly purplish red hue?
• Which characteristic is typically associated with full-drilled cultured pearls?
• Which country is known as the world's largest corundum marketing center?
• How many cleavage directions are typically found in feldspar, spodumene, and diopside?
• What is a xenocryst?
• What color is typically associated with the padparadscha sapphire?
• How are many colored stones traditionally mined?
• Which country is a known commercial source of chrome diopside?
• Which gemstone is known to occur in almost every color?
• Which of the following garnets can be orange in color?
• What attribute primarily determines the value of amber?
• Colored stones with higher values typically exhibit which characteristics?
• Which of the following terms refers to a gem-producing area?
• What does the term full-drilled refer to in cultured pearls?
• What causes abrasions in gemstones?
• What happens to dhun when treated?
• What coloring agents are used during lattice diffusion to produce a blue color in corundum?
• What is the definition of calcareous concretion in gemology?
• Which of the following gemstones is known for forming in hydrothermal conditions?
• In terms of cultivation methods, which pearl type uses the least invasive technique?
• What process does 'stabilization' typically involve when it comes to turquoise?
• What does the term 'Mine run' specifically refer to in the context of gemstones?
• What is a key locality known for hydrothermal gems?
• Which gemstone is known as "the blue diamond of the American West"?
• What characteristic defines jadeite?
• What factor can affect the value of an opal?
• What is a boulder opal?
• What type of environment is most likely to produce alluvial deposits?
• Specific gravity (SG) is defined as:
• Which treatment method for turquoise appeared in the 1980s and has been used extensively since then?
• What is the floating zone process used for in gemology?
• What does "new mine" refer to in the context of jadeite?
• Which type of coral is recognized as a variety of conchiolin coral?
• What is the most highly valued hue of blue sapphire?
• What distinguishes gem-quality benitoite?
• What is the purpose of most variations in a colored stone's face-up outline?
• Rhodolite is a blend of which two garnet types?
• What should be the ideal color of a sorting pad for colored stones?
• Which term describes volcanic activity that happens through a fissure?
• Which phenomenon is associated with light reflecting from the pavilion of a gemstone?
• What is the approximate hardness of Moldavite on the Mohs scale?
• Which country has the largest gem-consuming market in the world?
• What does an absorption spectrum show when viewed through a spectroscope?
• What type of gemstones are typically found in the commercial market?
• What is the primary color characteristic of kunzite?
• What is aragonite?
• A two-phase inclusion in a gem typically consists of:
• What type of calcium carbonate is specifically known as pink coral?
• What is the color characteristic of low zircons?
• What do polish lines indicate on the surface of a gem?
• What is mother-of-pearl primarily associated with?
• What is a pinpoint in the context of gemstones?
• Which gemstone is known for its amazing optical effect called chatoyancy?
• What is described as microcrystalline?
• Which of the following is an example of a gem variety?
• What geological process formed Myanmar's famous Mogok ruby deposits?
• Which trade term refers to a mixture of gem qualities that represents unsorted production from a particular mine?
• What does a scratch on a gem typically look like?
• Which gem retains stable color after irradiation under normal wearing conditions?
• What are weathered, thin-skinned jadeite boulders referred to as?
• What is the role of flux in the flux process?
• The first South Sea cultured pearl farm was founded in which country?
• What phenomenon is specifically caused by the scattering of light in some gemstones?
• Which type of jadeite is known for being bleached and impregnated?
• What is the primary focus of fracture filling treatments for gemstones?
• What does single refraction indicate about a gem's optical property?
• Which element is known to increase the amount of blue in an emerald's color?
• What type of pearls do mollusks typically produce when they live in cooler waters?
• What role do trace elements play in gemstones?
• What is the melt process in synthetic crystal growth?
• What is the primary characteristic of a negative crystal in a gemstone?
• Which of the following is NOT typically a characteristic of high-grade lapis lazuli?
• What effect does cutting deeper pavilions have on the color of gemstones?
• What is a common visual effect that can reduce the appeal of a transparent gemstone?
• Which term describes the type of fracture that extends from the surface inward in a gemstone?
• Which scale is used to express the hardness of a gemstone?
• What is a color change in gemstones?
• The term "silk" in relation to inclusions refers to what?
• Which gemstone exhibits a property known as "chatoyancy"?
• What is the best recommended method for cleaning pearls?
• Which of the following treatments is often used to enhance the color of kunzite?
• What is cobbing in the context of gemstone processing?
• What texture is often observed in pegmatite rocks?
• Which process involves using a heating unit to create a synthetic crystal from a rotating solid rod of chemicals?
• What occurs to light as it travels from one material to another, causing a change in speed and potentially direction?
• What distinguishes rhodolite garnet from other types of garnets?
• What is the first impression of an object's basic color referred to as?
• Which term describes the direction of single refraction in a doubly refractive gem?
• Which of the following best describes a gemstone's ability to resist wear and tear?
• What type of aggregate is tiger's-eye quartz classified as?
• What defines a gemstone?
• Which feature differentiates star sapphires from regular sapphires?
• What is the trade term for a type of labradorite?
• What is the finest texture category of jadeite called?
• What would be a tool used for finely manipulating small gems?
• What do trade terms in the jewelry industry often describe?
• What does double refraction in a gem's structure do?
• In order to be classified as a gem, a mineral must possess which three qualities?
• Which term refers to a gemstone's basic color determined by its light absorption?
• What is typically meant by the term "dyeing" in the context of gemstones?
• Which of the following gems is considered the most economically important?
• What treatment is commonly used to enhance the color of gemstones?
• What term describes inclusions causing light diffraction that resemble a fingerprint?
• What is the primary reason aimed at enhancing gemstone appearance in treatments?
• Which characteristic describes sagenitic quartz?
• What does the term "sagenitic" refer to in quartz?
• What is another name for the term 'authentic turquoise'?
• What is considered the finest color of turquoise?
• What type of opal typically shows bright orange to red colors due to its composition?
• What is a natural material composed of masses of mineral crystals known as?
• What is tortoise shell primarily composed of?
• Which type of twinning appears as if two crystal halves are mirror images of each other?
• What are sun spangles in amber?
• What defines an organic gem?
• What aspect of gemstones does 'texture' primarily refer to?
• What does the ceramic process entail?
• If an emerald weighs 3.50 carats and costs $10,500, what is the price per carat?
• What does the term 'cut' refer to in gemology?
• What is a major source of cat's-eye chrysoberyl?
• What is the definition of a 'point' in gemology?
• A substance that consists of atoms of only one kind is known as what?
• What do we call gemstone sizes that are cut to fit standard mountings?
• What level of transparency is considered the most valuable in jadeite?
• What is the most prized body color found in star corundum?
• What is the purpose of the pearl sac?
• What is chatoyancy in gemstones?
• A see-through area in a transparent gemstone's body color that usually results from the way the gem was cut is referred to as what?
• Which source became notable for producing good- to fine-quality sapphires in the late 1990s?
• What term refers to the quality ranking of gemstones based on specific criteria?
• What is the usual form in which benitoite is found?
• What does the term "color center" refer to?
• What is an included crystal?
• What mineral is known for the process of isomorphous replacement in garnets?
• What treatment is used to enhance the appearance of opal?
• What is the appearance of the feldspar with gridlike white streaks?
• Spessartine is primarily found in what type of geological formation?
• What is defined as an object's weight in relation to its size?
• What part does the mantle play in a mollusk?
• Which of the following gems is a cryptocrystalline aggregate?
• What does interference refer to in terms of light and gemstones?
• What is true about synthetic gem materials?
• What is a needle in terms of gemstone inclusions?
• Cryptocrystalline quartz is known as?
• Who is referred to as a 'processor' in the context of cultured pearls?
• What does a gem undergo during heat treatment?
• Which gemstone is considered a result of heat treatment from another stone?
• Which recent source is identified as the leading producer of small, commercial-quality aquamarine?
• How is most aquamarine's color improved?
• How can a cutter darken the color of a pale stone?
• What does 'hatchery-bred' refer to regarding mollusks?
• Which two primary processes are used in the production of synthetic gems?
• What organic material displays a structure called "engine turning"?
• What defines rutilated quartz?
• How is the toughness of jadeite best described?
• What does 'play-of-color' specifically describe?
• What type of gem is primarily created using the flux method?
• What synthetic production method gained rapid development due to laser research in the 1960s?
• What type of rock is produced from the eroded remains of existing rocks?
• What is meant by the term "parcel" in the gemstone trade?
• Which characteristic is specific to jet as a gemstone?
• For sorting purposes, what is the maximum diameter for round gems suitable for sieves?
• What is intended color zoning in gemstones?
• What is intervalence charge transfer?
• Which term is commonly used to describe sapphires that are intensely saturated in a range of pinkish orange to orange?
• A unit cell defines a mineral's:
• What process is known as skull melt in gem synthesis?
• What phenomenon describes the emission of visible light when a material is exposed to ultraviolet radiation?
• In gemology, which of the following describes a facet?
• Which clarity characteristic would generally have the greatest impact on a gem's marketability?
• What is Geuda primarily known for?
• What is the general term for a break in a stone?
• What is a typical shape for Zambian emerald crystals?
• What is the significance of beauty in relation to gems?
• What is the nacreous layer inside a pear-bearing mollusk's shell commonly called?
• Rubies from Pailin, Cambodia, share similarities with rubies from which other country?
• What is the purpose of colorless impregnation in gemstones?
• What does crazing in opal refer to?
• Which gem is known to crystallize in volcanic rock due to gases released by magma?
• What is one identifying feature of a triplet gem?
• Which deposit involves gems that have eroded from the source rock and remained in place nearby?
• What is an essential characteristic of gems besides beauty and durability?
• What does "parting" indicate in gemstone characteristics?
• Which area in Myanmar is known as the center of the jadeite-mining district?
• What is the main factor affecting the value of a gem regarding inclusions?
• What is the primary purpose of polishing in gem cutting?
• Which location has been supplying the most commercial-quality rubies since 1991?
• What is the primary component found in a two-phase inclusion?
• Which geological feature is associated with ruby deposits in Thailand and Cambodia?
• What characteristic is most commonly observed in sapphires?
• Which garnet is considered a variety of grossular garnet that is orange to brownish-red?
• What characterizes the process of hydrothermal growth?
• What is referred to by the term "facet grade"?
• Which of the following is a major risk for a gem's clarity rating?
• What is often used in the treatment of turquoise to enhance its durability?
• What is a characteristic of the cutting style known as 'step cut'?
• What defines a hollowback cabochon?
• Higher levels of saturation in colored stones are usually found in stones with what tone?
• Which synthetic gem production method is characterized by low cost and high volume?
• What does an oxidizing environment do to a gem during heat treatment?
• What does 'per-carat price' refer to?
• Where are the most desirable and rare blue natural spinels typically sourced?
• What does the term "erosion" refer to in geology?
• In the context of gem growth, what is a seed crystal?
• What is the recommended number of gems to group together when starting to count a large pile of small gems?
• What can heat do to amethyst's purple color?
• Which location is known for receiving rough gemstones from Mong Hsu into Thailand?
• What is a common characteristic of pearls cultivated in tropical waters?
• Which of the following opal types is known for its transparency and vivid colors?
• What is the trade name “Imperial” associated with?
• What is the first step in evaluating an opal?
• Aragonite is a crystallized form of what compound?
• What is the purpose of disclosure in gemstone transactions?
• How much can the diameter of cultured pearls in a hank vary from each other?
• In geology, what does the term 'plate' refer to?
• Which gem is notably produced in the Mogok region?
• What does the term "metric carat" signify in gemology?
• Kunzite is most commonly associated with which minerals?
• Materials cut free-size are typically associated with which type of stones?
• Which two factors determine an inclusion's impact on a gem's value?
• What is the most desirable color hue for emeralds?
• What is isomorphous replacement in mineralogy?
• The Zachery method is a treatment applied to which gemstone?
• What are the spots of color near the surface of a jadeite boulder called?
• What describes a flat break in a gemstone caused by included minerals?
• Which of the following describes a "color center" defect?
• How is synthetic opal primarily produced?
• Which colored stone variety faces cutting challenges because of its vulnerable cleavage planes?
• What does symmetry refer to in gemology?
• What kind of pearl is made from a bead nucleus?
• What environmental factor can significantly impact pearl luster?
• Which of the following gems is usually considered eye-clean?
• Which of the following is NOT a feature of watermelon tourmaline?
• Which type of rough is most likely to undergo cobbing?
• What is the trade term for top-color turquoise?
• Which mineral is described as a variety of amazonite?
• What does the term "extinction" refer to in the context of colored stones?
• What is the term for zircons that have undergone significant radiation damage?
• Which characteristic is typical of quartz?
• What is immature amber commonly known as?
• What is the table facet on a gemstone?
• Tahitian cultured pearls with a dark green-gray to blue-gray bodycolor and rose to purple overtones are referred to as what?
• What is the first step that farmers take with cultured pearls after harvest?
• Which treatment process commonly enhances the appearance of jadeite?
• What is necessary for yellow to reddish brown topaz to attain a treated pink color?
• What are tiny tension cracks in moonstone referred to as?
• Which garnet is known as a pinkish-orange mixture and is referred to by the trade term Malaya?
• How is density defined in the context of gemstones?
• How many points are in a metric carat?
• Finer-quality Kashmir blue sapphires typically exhibit what appearance?
• What does the mixed cut in gemstone cutting refer to?
• What function does the gonad serve in biological organisms?
• What aspect of gemstones does hardness measure?
• Which synthetic gem is produced solely by the hydrothermal growth process?
• What is the process of dyeing in gemstones?
• What is the term for a carved design that projects slightly from a flat or curved surface?
• What gem is formed by metamorphism?
• What is referred to as a twinning plane?
• What is the unique feature of hydrothermal growth in gem formation?
• When cutting an emerald to emphasize its most desirable color, what orientation is preferred for the table?
• What describes the medium texture category of jadeite?
• From what geological formation are Brazilian emeralds primarily mined?
• How far back does written information on dyeing gems date?
• What are seed pearls characterized as?
• Blue sapphires originating from basaltic rock typically have what characteristic?
• How many rays are typically seen in a star corundum?
• How readily available is green sapphire?
• What is a half-drilled cultured pearl used for?
• What type of rock is typically associated with the formation of sapphires?
• What causes thermal shock in gemstones?
• What is a 'preform' in gemstone processing?
• What should be the color of the background for grading a colored stone?
• Which of the following correctly defines spectrolite?
• Which term is associated with the appearance of gemstone sizes suited for mounting?
• Which of the following has the smallest crystal size?
• What is flux growth in the context of synthetic crystal formation?
• What is a negative crystal?
• What does "tone" refer to in the context of gemstones?
• What is a blemish in the context of gemstones?
• What characteristic distinguishes cryptocrystalline quartz from other quartz varieties?
• What does the term "intrusion" refer to in geology?
• Which treatment involves immersing opal in concentrated sulfuric acid?
• What is the primary outcome of using a pressurized steel container in synthesis?
• Approximately how many million years ago was most opal formed?
• Which of the following is not a characteristic of heavy minerals?
• What is a common trait found in sapphires sourced from Madagascar?
• Where does most gem-quality topaz come from?
• What does "cloud" refer to in gem evaluation?
• What term describes a laboratory-created gem that matches the natural stone in chemistry and structure?
• When discussing a gem, what typically does 'per-caret price' reflect?
• What does the term 'show points' specifically describe in jadeite?
• For a gemstone, what does "brilliance" primarily refer to?
• Where is rough gemstone material from Mogok typically brought into Thailand?
• Which cutting style features triangular or kite-shaped facets radiating from the center?
• How is mottling best described?
• What is the trade term for blue tourmaline?
• Which property of chrysoprase defines its appearance?
• Which type of cultured pearl is known for its unique dark color, primarily produced in French Polynesia?
• What does the term "organic" refer to in the context of gemstones?
• What is a dopstick used for in gemstone faceting?
• What is the primary cause of color in peridot?
• Which mechanism is used to synthesize some types of gemstones?
• What effect do gamma rays have on saltwater cultured pearls?
• Which element is generally used to enhance the luster of pearls during culturing?
• What type of cultured pearls are shaped and textured like rice grains?
• What is the total cost of a parcel of sapphires weighing 382.00 carats at a per-carat price of $80.00?
• What tool is described as a scoop in gemology?
• What color is hiddenite typically?
• In pearl culturing, which shape is considered the most challenging to produce?
• What defines a gem variety?
• What does 'high grading' refer to in mining terms?
• Which gemstone's treatment in the 1990s decreased consumer confidence?
• What type of rubies does Switzerland primarily export?
• Which of the following best defines an "oxidizing environment" in gem treatment?
• What is the 'pick price' in the context of gem selection?
• What is defined as a treatment in gemstones?
• What is chatoyancy in the context of gemstones?
• What phenomenon occurs when a gem's crystal structure splits light into two rays?
• What gem is known for having the widest range of colors?
• Which synthetic process utilizes an autoclave?
• What does the term conchiolin refer to in gemology?
• What does the technique of 'pulling' refer to in gem production?
• In which decade were the first flame-fusion star rubies produced?
• What is the importance of inclusions to a gemologist?
• What is a significant factor in determining the value of jet?
• What is the result of cobbing a gemstone?
• What does the term "stabilized turquoise" refer to?
• What phenomenon is referred to as "milk and honey" in gemstones?
• What is an atom?
• What is the color of imperial topaz?
• What is the term for a gem that is colored by an element included as part of its basic chemistry?
• Which type of color is considered the finest for aquamarine?
• What is mountain jade?
• What characteristic describes the visual appearance of a scratch on a gem?
• Which element is responsible for the green color in Tsavorite garnet?
• What characteristic best describes Type C jadeite?
• What are the four major types of cultured whole pearls?
• What is the most common color of untreated, natural topaz?
• In which clarity grades do definitions typically vary for each clarity type?
• Which of the following describes the type of rock changes due to direct contact with magma?
• What type of matrix is typically found as a layer in finished boulder opal?
• What is the primary advantage of flame fusion in synthetic gem production?
• What technological advancement significantly impacts cultured pearl farming?
• What does crystal structure refer to?