Quantcast

Metamorphic petrology Reference Libraries

Page 1 of about 7 Articles
Biotite
2005-05-26 12:03:39

Biotite is a common phyllosilicate mineral that contains potassium, magnesium, iron and aluminium. It is sometimes called "iron mica" and is found in granitic rocks, gneisses, and schists. Like other mica minerals, biotite has a highly perfect basal cleavage, its flexible sheets easily flaking off. It has a hardness of 2.5 - 3, a specific gravity of 2.7 - 3.1, is colored greenish to brown or...

Gneiss
2005-05-26 10:50:45

Gneiss is a common and widely distributed type of rock formed by high grade regional metamorphic processes from preexisting formations that were originally either igneous or sedimentary rocks. Gneissic rocks are coarsely laminated and largely recrystallized but do not carry large quantities of micas, chlorite or other platy minerals. Gneisses that are metamorphosed igneous rocks or their...

Kyanite
2005-05-26 09:41:33

The mineral kyanite is an aluminium silicate of the sillimanite group (along with andalusite and sillimanite), also called alumino-silicate. It has the formula Al2O3·SiO2 (Al2SiO5). Its hardness varies widely depending on its crystallographic direction, from 5 to 7.5, and it has a specific gravity of 3.56-3.67. It is translucent, usually blue, but possibly white, gray, green, or black. It...

Marble
2005-05-26 08:52:39

Marble is metamorphosed limestone, composed of fairly pure calcite (a crystalline form of calcium carbonate, CaCO3). It is extensively used for sculpture, as a building material, and in many other applications. Faux marble or faux marbling is a wall painting technique that imitates the color patterns of real marble (not to be confused with paper marbling). Marble dust can be combined with...

Muscovite
2005-05-26 08:35:42

Muscovite, also known as potash mica, is a phyllosilicate mineral of aluminium and potassium. It has a highly perfect basal cleavage yielding remarkably thin laminae (sheets), which are often highly elastic. Muscovite has a hardness of 2 - 2.25 and a specific gravity of 2.76 - 3. It can be colorless or tinted through grays, browns, greens, yellows, or rarely violet or red, and can be...

Sillimanite
2005-05-25 17:30:59

Sillimanite is an alumino-sillicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist B. Silliman (1779-1824). Occurrence Sillimanite is one of three alumino-sillicate polymorphs, the other two being andalusite and kyanite. A common variety of sillimanite is known as fibrolite, so named because the mineral appears like a bunch of fibres twisted...

Slate
2005-05-25 17:09:09

Slate is a fine-grained, homogeneous, sedimentary rock composed of clay or volcanic ash which has been metamorphosed (foliated) in layers (bedded deposits). Slate can be made into roofing shingles ('roofing slates' in the United Kingdom), because it has two lines of breakability: cleavage and grain. This makes it possible to split slate into thin sheets. Slate is mainly composed of quartz...

Word of the Day
megalophonous
  • Having a loud voice; vociferous; clamorous.
  • Of grand or imposing sound.
The word 'megalophonous' comes from Greek roots meaning 'big' and 'sound'.