Some minerals can be used as gemstone raw materials and natural pigments because of their bright colors. For example, red or blue corundum, green beryl as gem materials; malachite green, maroon hematite, etc. can be used as natural pigments. The color of a mineral is the result of the absorption of light waves by minerals at different wavelengths in white light. If the light waves of various wavelengths are generally and uniformly absorbed, black, gray, white, and the like are present depending on the degree of absorption. Such as the selective absorption of light waves of various wavelengths, it presents a variety of more vivid colors. For transparent minerals, the color of all transmitted light waves is the color of the mineral (such as natural sulfur , which is a transparent mineral, which can be considered as it absorbs the purple, blue, green, orange and red light waves in the transmitted light. It is yellow through more yellow light waves; for opaque minerals, its color is mainly determined by the color of the surface reflected light waves (such as the yellow light, which is mainly reflected in the surface of pyrite, so it is yellow) White calcite and natural silver are respectively expressed as white and generally absorbed and reflected by transmitted light waves and reflected light waves. The same minerals produced under different geological conditions often differ in color. The sphalerite (of ZnS), which is formed when the temperature is higher, the more iron containing, its color is black or brown and black is easy; temperature is not high as it is formed, containing less iron is thus rendered shallower Yellow, brownish yellow. Like a silky satin-like mineral, the ability to reflect the mineral surface is called gloss. Physical optics tells us that the strength of mineral luster depends on the absorption of visible light by minerals. The larger the absorption, the larger the reflection and the stronger the gloss, and vice versa. Mineral gloss grade: generally divided metallic luster and non-metallic luster, gloss subdivided into non-metallic semi-metallic luster, gloss and magic glass luster. The following numerical indicators are available for reference: Metallic gloss N>3, R=20-95% Semi-metallic luster N=2.6-3.0, R=8-20% Diamond Gloss N=1.9-2.6, R=10-29% Glass gloss N=1.3-1.9, R=2-10% Since the gloss is related to the streaks and the transparency, the observer can judge the gloss level by matching the streaks and the transparency. The logo that divides the naked eye into the metallic gloss level is as follows: The metallic luster is markedly metallic, opaque, and the streaks are black. E.g. natural copper, galena, and magnetite. The semi-metallic luster is light metal, translucent, and the streaks are mainly dark. Such as cinnabar, black sphalerite and so on. Diamond gloss is diamond -like, translucent or transparent, and the streaks are light, colorless or white. For example, diamond, scheelite , light-colored sphalerite, and the like. The glass luster is glassy, ​​transparent, and the streaks are colorless or white. Such as crystal , feldspar , ice stone and so on. If the mineral surface is not flat, or has small pores, or is not a monomer but an aggregate, the amount of light reflected from the surface increases the amount of light scattered by undergoing multiple refractions and reflections, resulting in the following special luster: Silky shiny transparent mineral, when it is a fibrous aggregate, the surface is silky and bright. Such as fibrous gypsum , asbestos and the like. Pearl-gloss transparent mineral with pearly luster on the extremely complete cleavage surface. Such as mica , plaster and so on. Grease-gloss transparent mineral, cleavage is not developed, and it has a grease-like brilliance on an uneven fracture. Such as quartz, garnet and the like apatite. Asphalt luster Translucent or opaque black mineral, cleavage is not developed, with asphaltic light on uneven fractures. For example, cassiterite , magnetite, asphalt uranium ore. A mineral with a lustrous powdery and earthy aggregate with a dull surface. Such as kaolinite, limonite and so on. Mineral light artifacts can be used to identify gems. Fake stones are often glassy, ​​and the precious stones are diamond, silky, fat and pearly. , China, manufacturers, suppliers, factory, price, quotation, for sale, high quality, high performance Hubei Chenglongwei Special Purpose Vehicle Co., Ltd. , https://www.clw-automobile.com
The nature of minerals: color, luster
Color is one of the important optical properties of minerals. Many minerals have their special color, so it can be used as an identification feature of minerals. For example the malachite green particular, special blue blue copper ore minerals are important features of these identification.