Lustre
Lustre
Another thing you can see when you hold a mineral up to a light is its lustre - the way light is reflected from it.
Is it shiny or dull? Can you see your reflection in your mineral? What does the lustre look like when you hold your mineral up to a light?
There are several kinds of lustre. Most minerals have a vitreous (glassy) lustre or a metallic lustre. In the pictures below, the quartz has a vitreous lustre just like a drinking glass. The galena has a metallic lustre like metal wire.
Sometimes we can use lustre to identify minerals. Only certain minerals ever have a pearly, waxy or greasy lustre. A diamond crystal has a brilliantly shiny adamantine lustre - the word adamantine comes from the ancient Greek word for diamond.
Can you imagine what a mineral with a pearly lustre would look like? What about a waxy or dull lustre?
