Natural gemstones include minerals and organic materials such as emeralds, rubies, sapphires, amber and so on.

Synthetic and Simulant are terms used by the USBM for laboratory grown gemstones. Laboratory grown synthetic gemstones have essentially the same appearance and optical, physical, and chemical properties as the natural material.

Synthetic gemstones produced in the United States include alexandrite, coral, diamond, emerald, garnet and so on.

Laboratory grown simulants have an appearance similar to that of a natural gemstone but have different optical, physical, and chemical properties. The Gemstone Simulants produced in the United States include coral, cubic zirconia, lapis lazuli, malachite, and turquoise. Colored and colorless varieties of cubic zirconia are the major simulants produced.