What luster is typical of non-diamond simulants and among the best?

• A. Subadamantine and vitreous
• B. Metallic and adamantine
• C. Pearly and waxy
• D. Silky and resinous

Answer: (A)

Luster describes how light reflects off a gem’s surface, and the terms used here tell you a lot about how non‑diamond simulants typically appear. Non-diamond simulants usually show a glassy, bright surface described as vitreous. Some high-quality simulants can push the brightness toward diamond-like levels, which is captured by the term subadamantine—luster that is very strong but just short of true diamond’s adamantine brilliance. This combination—glassy (vitreous) with the occasional near-diamond sparkle (subadamantine)—is what you commonly see in non-diamond simulants and represents the strongest luster they can achieve outside of actual diamond.

Metallic luster is characteristic of metals or metal-coated surfaces and isn’t typical for gemstone simulants. Pearly and waxy describe pearls or waxy-looking materials, not the common diamond simulants. Silky and resinous describe fibrous or resinous substances, which again don’t match the usual surface reflection of common simulants. So the luster that best fits non-diamond simulants, and is among their strongest, is subadamantine and vitreous.