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Granite (/ ˈɡrænɪt / GRAN-it) is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies underground.
In the chart below, a year which is listed within parentheses represents the year during which that mineral, rock, stone or gemstone was officially adopted as a state symbol or emblem. Table of minerals, rocks, stones and gemstones
Mineral symbols are most commonly represented by three-lettered text symbols, although one-, two- and four-lettered symbols also exist. Four methods of nomenclature are used: [ 3 ][ 5 ] The initial letters of a name, for example: cyanotrichite: Cya and mitscherlichite: Mits. A combination considered characteristic of the mineral name, for ...
The S-type Granya Granite shows the characteristic white feldspars, grey quartz, and black biotite, the highly reflective mineral is muscovite. The S-type Strathbogie Granite crops out in the Strathbogie Ranges of Australia. A hand sample from the Strathbogie Granite has a porphyritic texture with larger crystal of grey quartz, called ...
A-type granite. A-type granite is a particular category of the S-I-A-M or 'alphabet' system which classifies granitoids and granitic rock by their photoliths or source. [1][2] The 'A' stands for Anorogenic or Anhydrous, as these granites are characterized by low water content and a lack of orogenic or transitional tectonic fabric. [3]
The following is a list of rock types recognized by geologists. There is no agreed number of specific types of rock. Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type. Additionally, different classification systems exist for each major type of rock. [1]
Mohs scale. The Mohs scale (/ moʊz / MOHZ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material. The scale was introduced in 1812 by the German geologist and mineralogist Friedrich Mohs, in his book Versuch einer ...
I-type granite. I-type granites are a category of granites originating from igneous sources, first proposed by Chappell and White (1974). [1] They are recognized by a specific set of mineralogical, geochemical, textural, and isotopic characteristics that indicate, for example, magma hybridization in the deep crust. [2]