Name the three main identity categories you would encounter in gem testing.

• A. Natural diamond, lab-grown diamond (HPHT/CVD), and simulants (e.g., CZ, moissanite).
• B. Natural diamond, treated diamond, and simulants.
• C. Natural diamond, synthetic diamond, and colored gemstones.
• D. Natural diamond, lab-grown diamond, and glass.

Answer: (A)

The main idea here is to recognize the three identity categories you use when identifying a diamond: natural diamond, lab-grown diamond, and simulants. Natural diamonds are formed in the Earth over geologic time and are genuinely the mineral diamond. Lab-grown diamonds are real diamonds too, created in a controlled lab environment through processes like HPHT (high pressure high temperature) or CVD (chemical vapor deposition); they have the same chemical composition as natural diamonds but a different growth history. Simulants are materials that imitate diamond’s appearance or some properties but are not diamond themselves, such as cubic zirconia and moissanite.

This trio is why the option listing natural diamond, lab-grown diamond (HPHT/CVD), and simulants (e.g., CZ, moissanite) is the best choice. The other options mix in treated diamonds, colored gemstones, or glass, which are not the three primary identity categories used to classify diamonds for testing and disclosure.