Search results
Results from the WOW.Com Content Network
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 metamorphic facies is not usually considered when classifying metamorphic rock based on protolith, mineral mode, or texture. However, a few metamorphic facies produce rock of such distinctive character that the facies name is used for the rock when more precise classification is not possible. The chief examples are amphibolite and eclogite.
Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO 3) or dolomite (CaMg (CO 3) 2) that have recrystallized under the influence of heat and pressure. [1] It has a crystalline texture, and is typically not foliated (layered), although there are exceptions. In geology, the term marble refers to metamorphosed ...
Slate. Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale -type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic rock. [1] Foliation may not correspond to the original sedimentary layering, but instead is in ...
Gneiss. Metamorphic rock. Sample of gneiss exhibiting "gneissic banding". Gneiss (/ naɪs / nice) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. This rock is formed under pressures anywhere from 2 ...
e. In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's outer solid layer, the crust, and most of its interior, except for the liquid outer core and pockets ...
A mixture of other minerals, often including pyrite. Lapis lazuli (UK: / ˌlæpɪs ˈlæz (j) ʊli, ˈlæʒʊ -, - ˌli /; US: / ˈlæz (j) əli, ˈlæʒə -, - ˌli /), or lapis for short, is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color.
Quartzite. 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. Pure quartzite is usually white to grey, though quartzites often occur in various shades of pink and ...