Schist
A species of Metamorphic Scientific name : Schist RockType : Metamorphic
Schist, A species of Metamorphic
Scientific name: Schist
RockType: Metamorphic
Content
Description People often ask General Info
Photo By James St.John , used under CC-BY-2.0 /Cropped and compressed from original
Description
Schists are metamorphic rocks, usually formed from shale or mudstone, that have an abundance of large, platy grains – though what exactly those grains are made from varies greatly across specimens. Schist has few industrial uses, though this rock can host large, gem-quality crystals, including garnets, emeralds, sapphires, and rubies.
Physical Properties
Colors
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Texture
Foliated
People often ask
General Info
How to Select
Schist, a metamorphic rock known for its flaky nature and shiny appearance, is desired based on several factors:
1.Mineral Composition: schist can contain various minerals like garnet, mica, or graphite. Those with significant amounts of precious or semi-precious minerals are typically more valuable.
2.Texture and Foliation: The appeal of schist largely lies in its foliated (layered) texture. Schist with prominent, well-defined foliations that readily split into thin, flexible sheets is considered more desirable.
3.Color: Color depends on mineral composition, but varieties with vibrant or unusual colors can be especially desirable. Sometimes schist may have bands or patches of different colors, adding to their aesthetic appeal.
4.Luster: Mica-rich schist has a distinctive shine or sparkle, which can increase its desirability.
5.Size and Shape: A larger piece of high-quality schist without fractures or deformities is generally more valued.
In summary, when purchasing schist, look for a specimen with a rich mineral composition, pronounced foliation, appealing color, high luster, and large size. Remember, the most desirable qualities or varieties of schist largely depend on its intended use and the preferences of the individual user or buyer.
Usage
Schist is a very durable rock, and because of that it has been used for centuries in construction. Buildings constructed from this rock can last for hundreds of years, and in addition to walls and flooring, it can be used in roofing and pillars. Schist is a common addition to many paints and is also used in jewelry.
Formation
During metamorphism, rocks which were originally sedimentary, igneous or metamorphic are converted into schists and gneisses. If the composition of the rocks was originally similar, they may be very difficult to distinguish from one another if the metamorphism has been great. A quartz-porphyry, for example, and a fine grained feldspathic sandstone, may both be converted into a grey or pink mica-schist. Usually, however, it is possible to distinguish between sedimentary and igneous schists and gneisses. If, for example, the whole district occupied by these rocks has traces of bedding, clastic structure, or unconformability, then it may be a sign that the original rock was sedimentary.
Photo By James St.John , used under CC-BY-2.0 /Cropped and compressed from original