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2. Metamorphic rock - Wikipedia

   en.wikipedia.org/wiki/Metamorphic_rock

   For instance, the small calcite crystals in the sedimentary rock limestone and chalk change into larger crystals in the metamorphic rock marble. [12] In metamorphosed sandstone, recrystallization of the original quartz sand grains results in very compact quartzite, also known as metaquartzite, in which the often larger quartz crystals are ...

3. Greywacke - Wikipedia

   en.wikipedia.org/wiki/Greywacke

   Greywacke or graywacke (German grauwacke, signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness (6–7 on Mohs scale), dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or sand-size lithic fragments set in a compact, clay-fine matrix.

4. List of rock types - Wikipedia

   en.wikipedia.org/wiki/List_of_rock_types

   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 ...

5. List of sandstones - Wikipedia

   en.wikipedia.org/wiki/List_of_sandstones

   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 ...

6. Metamorphism - Wikipedia

   en.wikipedia.org/wiki/Metamorphism

   Metamorphism is the set of processes by which existing rock is transformed physically or chemically at elevated temperature, without actually melting to any great degree. The importance of heating in the formation of metamorphic rock was first recognized by the pioneering Scottish naturalist, James Hutton , who is often described as the father ...

7. Gneiss - Wikipedia

   en.wikipedia.org/wiki/Gneiss

   In other words, the rock was metamorphosed at a temperature in excess of 600 °C (1,112 °F) at pressures between about 2 to 24 kbar. Many different varieties of rock can be metamorphosed to gneiss, so geologists are careful to add descriptions of the color and mineral composition to the name of any gneiss, such as garnet-biotite paragneiss or ...

8. Quartzite - Wikipedia

   en.wikipedia.org/wiki/Quartzite

   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.

9. Conglomerate (geology) - Wikipedia

   en.wikipedia.org/wiki/Conglomerate_(geology)

   Carmelo Formation (conglomerate) at Point Lobos Nagdong Formation at Sangju. Conglomerate (/ k ən ˈ ɡ l ɒ m ər ɪ t /) is a sedimentary rock made up of rounded gravel-sized pieces of rock surrounded by finer-grained sediments (such as sand, silt, or clay).