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Mineralogy Reference Libraries

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Amphibole
2005-05-26 12:19:41

Amphibole defines an important group of dark-colored rock-forming inosilicate minerals composed of double chain SiO4 tetrahedra linked at the vertices and generally containing ions of iron and/ or magnesium in their structures. In chemical composition and general characteristics they are very similar to the pyroxenes and, like them, fall into three series according to their system of...

Calcite
2005-05-26 11:59:32

he mineral calcite is a calcium carbonate corresponding to the formula CaCO3 and is one of the most widely distributed minerals on the Earth's surface. It is a common constituent of sedimentary rocks, limestone in particular. It is also the primary mineral in metamorphic marble. It also occurs as a vein mineral in deposits from hot springs, and also occurs in caverns as stalactites and...

Celestite
2005-05-26 11:56:59

Celestite (SrSO4) is a mineral consisting of strontium sulfate. The mineral is also known as celestine and is named for its occasional delicate blue color. Celestite occurs as crystals, and also in compact massive and fibrous forms. It is mostly found in sedimentary rocks, often associated with the minerals gypsum, anhydrite, and halite. The mineral is found worldwide, usually in small...

Chalcocite
2005-05-26 11:32:33

Chalcocite, copper(I) sulfide (Cu2S), is an important copper mineral ore. It is opaque, being colored dark-gray to black with a metallic luster. It has a hardness of 2½ - 3. It is a sulfide with an orthorhombic crystal system. Chalcocite is sometimes found as a primary vein mineral in hydrothermal veins. However, most chalcocite occurs in the supergene enriched environment below the...

Chert
2005-05-26 11:30:45

Chert is a fine-grained silica-rich cryptocrystalline sedimentary rock that may contain small fossils. It varies greatly in color from white to black, but most often manifests as gray, brown, grayish brown and light green to rusty red; its color is an expression of trace elements present in the rock, and both red and green are most often related to traces of iron (in its oxidized and reduced...

Corundum
2005-05-26 11:05:25

Corundum is the crystalline form of aluminium oxide and one of the rock-forming minerals. Corundum is naturally clear, but can have different colors when impurities are added. Transparent specimens are used as gems, called ruby if red, while all other colors are called sapphire. The word corundum comes from the Hindi kurand. The oxygen atoms in corundum are arranged in a hexagonal...

Salt Halite
2005-05-26 10:40:24

Halite is the mineral of sodium chloride, NaCl, commonly known as rock salt. Halite forms isometric crystals. The mineral is colorless to white, light blue, dark blue, and pink. It commonly occurs with other evaporite deposit minerals such as several of the sulfates, halides and borates. Halite occurs in vast beds of sedimentary evaporite minerals that result from the drying up of enclosed...

Limonite
2005-05-26 09:37:09

Limonite Limonite is a ferric hydrate of varying composition, the generic formula is frequently written as FeO(OH)·nH2O, although this is not entirely accurate as Limonite often contains a varying amount of oxide compared to hydroxide. Together with hematite, it is mined as ore for the production of iron. Limonite is heavy and yellowish-brown. It is not a true mineral, however, but a...

Mica
2005-05-26 08:40:58

The mica group of minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition. The highly perfect cleavage, which is the most prominent characteristic of mica, is explained by the hexagonal sheet-like arrangement of its atoms. The word "mica" is thought...

Quartz
2005-05-25 18:55:31

Quartz is the second most abundant mineral in the Earth's crust. It has a hexagonal crystal structure made of trigonal crystallized silica (silicon dioxide, SiO2), with a hardness of 7 on the Mohs scale. Density is 2.6 g/cm³. The typical shape is a six-sided prism that ends in six-sided pyramids, although these are often distorted, or so massive that only part of the shape is apparent from a...

Word of the Day
caparison
  • A cloth or covering, more or less ornamented, laid over the saddle or furniture of a horse, especially of a sumpter-horse or horse of state.
  • Clothing, especially sumptuous clothing; equipment; outfit.
  • To cover with a caparison, as a horse.
  • To dress sumptuously; adorn with rich dress.
This word ultimately comes from the Medieval Latin 'cappa,' cloak.
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