The way light bounces off of a mineral's surface is described as its luster. There are a number of specific descriptions or categorizations for a mineral's luster. Do keep in mind that luster is related to the opacity/transparency of a mineral in addition to the surface conditions, crystal habit, and index of refraction. Luster is unrelated to the color of a mineral or gem.
Dull, or earthy. This describes minerals with a matte surface,...
The way light bounces off of a mineral's surface is described as its luster. There are a number of specific descriptions or categorizations for a mineral's luster. Do keep in mind that luster is related to the opacity/transparency of a mineral in addition to the surface conditions, crystal habit, and index of refraction. Luster is unrelated to the color of a mineral or gem.
Dull, or earthy. This describes minerals with a matte surface, or one that is not shiny. Chert and flint fall into this category.
Waxy, or waxlike. These minerals may look like they have a coating of wax, and can be a little bit reflective. Coral and serpentine fall into this category.
Pitchy, or pitchlike. This means that a mineral looks similar to tar. Many radioactive minerals like uranininite fall into this category.
Greasy, like the mineral has been covered in an oily substance. Opal falls into this category.
Pearly, or mother-of-pearl sheen, describes minerals which look pearlescent. Muscovite and stilbite are two examples of pearly minerals.
Silky minerals look similar to the textile silk. They are composed of very fine fibers. The dangerous mineral asbestos falls into this category.
Resinous, or resinlike, describes minerals which look like resin or plastic. Amber is a famous type of resinous mineral, and is actually fossilized resin from a tree.
Adamantine, also called brilliant or diamondlike, has a very reflective and refractive luster. Like the name implies, diamonds fall into this category.
Vitreous, or glassy, describes minerals which look like glass. The quartz varieties falls into this category.
Submetallic minerals are those which look similar to metal but are not as reflective. Sphalerite is a perfect example of a mineral with submetallic luster.
Metallic minerals are highly opaque and reflective, like pyrite.
No comments:
Post a Comment