What is referred to by the term "facet grade"?

The term "facet grade" specifically refers to rough gemstones that possess the necessary qualities—such as transparency, clarity, and minimal inclusions—that make them suitable for cutting into faceted gemstones. Faceting is a technique used to enhance the aesthetic appeal of gemstones by creating multiple facets that reflect light, thus maximizing brilliance and sparkle. Therefore, rough material categorized as facet grade is typically of better quality than that which would only yield cabochons or other non-faceted cuts.

In contrast, the other options do not accurately define facet grade. For instance, while low-quality rough might not be suitable for faceting, saying that facet grade refers exclusively to low-quality rounds doesn't consider the essential characteristic of transparency. Similarly, high-quality gemstones ready for the market reflect a finished and polished product rather than rough material qualifying for faceting. Lastly, while any gemstone that has been altered by cutting might include faceted gems, this definition is too broad and does not specifically describe the quality or suitability concerning faceting. Therefore, the ideal answer encapsulates the essential quality of rough that permits the creation of faceted gems.