Luster
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LUSTER
This is the sparkling effect produced by the reflection of light as it strikes the surface of a stone. Its intensity is determined by the refractive index of the stone and how skillfully it has been polished, and can be altered if the stone contains too many inclusions.
The characteristic luster of the diamond, the brightest of all, is almost equaled by other gems with a high refractive index, such as zircon and demantoid.
Depending on its nature, luster can be vitreous, resinous, waxy, pearly or silky.
