Luster is the intensity and quality of light that is reflected from the surface of a gem. The first (or the next) opportunity that you have to see a spinel, play it under a light. You will be impressed by its brilliant luster!

Spinel has the ability to accept one of the brightest polishes of all gems. The luster of a polished spinel is only exceeded by diamond, sphene and zircon – these gems have a polish luster known as adamantine.

Spinel has a subadamantine luster. The only other gems with that polish luster listed in the GIA Gem Reference Guide and the GIA Gem Identification Lab Manual are the corundums (ruby and sapphire); the chrysoberyls (chrysoberyl, alexandrite, and cat’s-eye chrysoberyl); and, some varieties of garnet (andradite, malaia, and spessartine).