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Gem talk: What exactly is luster?

Learning about gems is a science in its own right. But that doesn’t mean you have to go back to school to learn.

Education at Joseph Schubach Jewelers is quick, easy and best of all…free! 


So let’s talk luster. The terminology surrounding luster is a bit more complicated than the terminology surrounding brilliance (the amount of light reflected out of the crown of the gem to the eye). Brilliance is rather easy to describe: more or less. Luster language gets a little more dense.

But first, what is luster? Luster is the manner by which light interacts with the surface of a gem. The word holds its origins in Latin. Lux (meaning “light”) and generally implies radiance, gloss or brilliance.

A glass-like luster (called vitreous) is most frequently found in transparent faceted gems such as sapphire, emerald, ruby and tourmaline. Other “lustrous” names? Silky (such as tiger’s eye), resinous (think amber) and greasy (yep…that would be jadeite, unfortunately).

That was pretty painless, right? Better yet, just call us for more information on luster. We love talking shop!