What defines an organic gem?

An organic gem is defined as one that is derived from biological sources, meaning it originates from the remains of living organisms. Examples of organic gems include pearls, which are formed within the shells of mollusks; amber, which is fossilized tree resin; and coral, which is produced by marine coral polyps. These materials showcase the interaction between biological processes and mineral growth.

The other options do not hold true to the definition of organic gems. Gems formed from inorganic minerals refer to traditional gemstones like diamonds or sapphires. Man-made gems, while increasingly popular and valuable, are synthetic and not classified as organic. Similarly, gems modified by heat are often treated stones that still retain their inorganic origin, thus do not qualify as organic gems. Understanding the classification of gems helps in appreciating their origins and the processes that lead to their formation.