lus·ter | ˈlə-stər
noun
The appearance of a material's surface, as determined by the quantity and quality of light reflected
Luster is a term used to describe the amount of surface reflection or gloss on a gemstone. It directly refers to the appearance of a specific material’s surface and is used to describe gemstones in relation to the overall quality and quantity of light that they reflect. This relates to the refractive index of the stone - the natural light reflected by it - and the amount by which it can be polished to increase luster in the finished stone. Harder gemstones are able to be polished more substantially and therefore generally have a higher level of luster than those with a lower hardness rating.
