Which of the following is an example of an organic gem?

Amber is considered an organic gem because it is formed from the fossilized resin of trees, a natural substance produced by living organisms. This organic origin distinguishes it from minerals, which are inorganic and typically formed through geological processes. Organic gems like amber can have unique properties and characteristics, such as inclusions of ancient insects or plant matter trapped within them, adding to their uniqueness and historical significance.

In contrast, emerald, opal, and diamond are all inorganic minerals. Emerald is a variety of beryl with a specific chemical composition, opal is a mineraloid known for its play of color, and diamond is a crystalline form of carbon. Each of these gemstones is formed through processes deep within the Earth, involving high temperatures and pressures, which further highlights the distinction between organic and inorganic gems.