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Evaporite – Water-soluble mineral deposit formed by evaporation from an aqueous solution; Flint – Cryptocrystalline form of the mineral quartz; Geyserite – Form of opaline silica often found around hot springs and geysers; Greywacke – Sandstone with angular grains in a clay-fine matrix; Gritstone – Hard, coarse-grained, siliceous ...
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith ) is subjected to temperatures greater than 150 to 200 °C (300 to 400 °F) and, often, elevated pressure of 100 megapascals (1,000 bar ) or more, causing profound physical or chemical changes.
The equivalent Greek-derived term is psammite, though this is more commonly used for metamorphosed sediments. Since it refers to grain size rather than chemical composition, the term is used for example in the classification of clastic carbonatic limestones, as the granulometrically equivalent term sandstone is not appropriate for limestone.
This results in a banded, or foliated, rock, with the bands showing the colors of the minerals that formed them. Foliated rock often develops planes of cleavage . Slate is an example of a foliated metamorphic rock, originating from shale , and it typically shows well-developed cleavage that allows slate to be split into thin plates.
Psammite (Greek: psammitēs "(made) from sand", from psammos "sand") [1] is a general term for sandstone.It is equivalent to the Latin-derived term arenite [2] [3] and is commonly used in various publications to describe a metamorphosed sedimentary rock with a dominantly sandstone protolith. [4]
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains, cemented together by another mineral. Sandstones comprise about 20–25% of all sedimentary rocks.
Quartzite can have a grainy, glassy, sandpaper-like surface. Quartzite is a hard, non-foliated metamorphic rock which was originally pure quartz sandstone. [1] [2] Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts.
Bäch Sandstone: by the Lake Zürich; Bern Sandstone: quarry sites near Bern in Ostermundigen, Krauchthal and by the Gurten; Bollingen Sandstone (also Buchberg Sandstone, Uznaberg Sandstone, Bollinger-Lehholz Sandstone and Güntliweid Sandstone): Rapperswil-Jona by the Upper Lake Zürich; Grès à cailloux roulés: near Avenches; Grès de ...