The largest category of minerals, accounting for almost known mineral crust 2 / 3, can be further divided into silicate, carbonate, sulfate and so on.
Cation of metal elements in carbonate and carbonate salts formed phase compounds. Carbonate minerals in 95 or so species, including calcite and dolomite are very widespread in nature, minerals, and many carbonate minerals is an important non-metallic mineral raw materials, but also extract Fe, Mg, Mn, Cu, etc. metals and radioactive elements Th, U of important mineral source of great economic significance. In carbonate minerals, the main anion [CO3] 2 -, cation mainly Ca2 +, Mg2 +, followed by Na +, Fe2 + and Cu2 +, Zn2 +, Pb2 +, Mn2 +, Bi3 + and so on. Some carbonate minerals have a good single crystal, but also showed a massive, granular, such as radial and earthy collection of forms. Most of the carbonate mineral is colorless or white, copper-green or bright blue who was, who was red roses manganese, or iron containing rare earths are brown, cobalt are pale red, yellow uranium were . Mineral hardness is not, generally around 3. The largest is the hardness of rare earth carbonate minerals, but not more than 4.5, the main non-metallic luster. Carbonate minerals are mainly exogenous origin, widely distributed, can form large areas of marine sedimentary strata. Generated by the majority of carbonate rocks in magmatic hydrothermal stage.
Cation sulfate minerals are metals and sulfate salts formed phase compounds. Because sulfur is a variable price element was different in nature, it can form different valence minerals. When it the highest four valence S6 + and O2-binding as [SO4] 2 -, then with metal elements that form a sulfate ion. In sulfate minerals, metals and sulfate radical cation compound has more than twenty. The most important is the Ca2 +, Mg2 +, K +, Na +, Ba2 +, Sr2 +, Pb2 +, Fe3 +, Al3 +, Cu2 +. Sulfate minerals currently known species and 170 species. Although they account for only 0.1% of the total weight of the crust, but they are in the gypsum, anhydrite, barite, Glauber's salt, etc. are able to integrate the rich deposits have industrial significance. Most of sulfate mineral salts composition more complex, so the crystal structure of lower symmetry, are mainly monoclinic and orthorhombic. And because most of the sulfate mineral containing water, it is the most prominent physical properties of low hardness, generally between 2-3.5. In addition, the color is generally colorless and white, the proportion of generally not large, about 2-4. Sulfate mineral formation requires aerobic conditions the concentration of large and low temperature, so the surface is most suitable for the formation of some sulfate minerals in place. In this class of minerals within the formation due to exogenous causes far more important. Which the original metals from sulfide oxidation of sulfate minerals, in the types of minerals account for almost half of the class. Chemical deposition in the basin of the sulfate minerals are potassium, sodium, calcium, magnesium, barium, aluminum sulfate water. The endogenous origin of hydrothermal sulfate minerals, mainly barium, calcium, strontium, aluminum sulfate anhydrous, low temperature hydrothermal veins found in or as a product of low-temperature hydrothermal wall rock alteration.
Chromate minerals are metals and chromate ion from the salt phase compounds. Chromium is an element of variation in nature, appear in different valence state and the formation of different minerals. As in nature, most of the chromium oxide and chromium in the composition of silicates, and the number and composition of chromate mineral species are very small. Not more than ten kinds of the current data. Chromate mineral most notably characterized by a sharply colors. Usually yellow, orange, red or brown red, green, compared with the copper. Hardness is generally not high, between 2-3. Between the proportion of generally 2-3. Chromate mineral often formed under weathering product found in the oxidation zone deposit.
Tungstate and molybdate are metal elements, and tungstate ion and molybdate salts from the root phase compounds. Since the atomic radius of molybdenum and tungsten and the ionic radius of the same, and tungstate [WO4] 2 - and molybdate root [MoO4] 2 - are very similar nature, and therefore usually in the mineralogy of tungstate and molybdate classified as category. However, molybdenum is mainly combined with sulfur to form sulfide molybdenite, and molybdate molybdenite mineral is the product of oxidation, and the distribution of rare in nature. In contrast, most of tungstate tungsten minerals were formed, and often integrate the rich ore deposits. The few types of minerals, only more than twenty. Tungstate minerals, and the combination of tungstate ion, the limited number of species, mainly Ca2 +, Fe2 +, Mn2 +, Pb2 +, followed by Cu2 +, Zn2 +, Al3 + and so on. Molybdate combined with the root of the cationic species is less, mainly Ca2 +, Pb2 +, followed by the U4 +, Fe2 + and so on. Since the atomic weight of tungsten is large (183.86), which generally tungstate mineral density in 6-7.5g/cm3 between. As the atomic weight of molybdenum (95.95) than the tungsten is small, the proportion of mineral molybdate usually smaller than the tungstate minerals. Tungstate and molybdate hardness minerals are generally not high, not more than 4.5; the color of the minerals, in addition to wolframite red to black to dark brown, dark red-brown for the tungsten galena, black is black uranium molybdenum , the other mostly light. In this class of minerals, mineral water acid generated belong to the cause, mainly seen in the Gasification - high temperature hydrothermal deposits and the contact metasomatic deposits. Molybdate minerals belong to the exogenous origin, appeared in the oxidation zone.
Phosphate, arsenate and vanadate is a metallic element cations with phosphate, arsenate or vanadate phase compounds from the salts. Phosphorus, arsenic and vanadium in the chemical periodic table belong to the first V family, which combines with the O2-phosphate, arsenate and vanadate are very similar nature, and thus classified as a class of them. The more types of minerals are known to those of more than three hundred species, of which nearly two hundred kinds of phosphate, arsenate over a hundred species, of about thirty kinds of vanadate. But they have very few minerals, in addition to widely distributed in nature, most are very few. Their total only 0.7% of the crust. The larger the radius of the trivalent cation and divalent cations and phosphate, arsenate and vanadate anions such as combining to form a stable salt-free, the smaller the radius is often the formation of divalent cation salt water, a common cation can together form a double salt. The minerals, because it is more complex compounds, which lower the crystal symmetry to more. Most orthorhombic and monoclinic, and the rest belongs to triclinic crystal system, respectively, three and hexagonal crystal system, tetragonal, and equiaxed grains are only a few lines of several persons. As more complex composition, species are more changes in the physical properties of the large range. Color terms, all with pigment ions, such as iron, manganese, cobalt, nickel, copper, uranium, etc., the more intense the color appears. Furthermore, most minerals have a glassy luster. Generated by the phosphate minerals, but also exogenous origin. Due to the generation, most formed in the role of magmatism and pegmatite can also be formed in a contact metasomatic and hydrothermal; exogenous origin, is formed by a complex biochemical, or generated by the phosphate from the inside after changes in mineral formed by secondary minerals. By mineral species, the exogenous origin of the phosphate minerals within the formation due for more than more. Almost all of arsenate arsenide subjected to oxidation by the formation of secondary minerals. The formation of an independent mineral vanadium appeared limited. |
phosphate