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Granite (/ ˈ ɡ r æ n ɪ t / GRAN-it) is a coarse-grained 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. It is common in the continental crust of Earth, where it is found in igneous ...
Jaspillite – Banded mixture of hematite and quartz; Laterite – Product of rock weathering in wet tropical climates rich in iron and aluminium; Lignite – Soft, brown, combustible, sedimentary rock; Limestone – Type of sedimentary rock; Marl – Lime-rich mud or mudstone which contains variable amounts of clays and silt
Granite plutons can be grouped into suites and super suites by their source regions, which in turn are interpreted by comparing their compositions. This interpretation comes from the plotting of different element concentrations against the level of evolution of the granite, usually as percent silica or its magnesium to iron ratio.
[99] [100] Non-silicate minerals are subdivided into several other classes by their dominant chemistry, which includes native elements, sulfides, halides, oxides and hydroxides, carbonates and nitrates, borates, sulfates, phosphates, and organic compounds. Most non-silicate mineral species are rare (constituting in total 8% of the Earth's crust ...
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 phenocrysts, set in a finer grain matrix of quartz and feldspar. The darker, prismatic, phenocrysts in this sample of the Strathbogie Granite are cordierite.
Decomposed granite is a kind of granite rock that is weathered to the point that the parent material readily fractures into smaller pieces of weaker rock. Further weathering yields material that easily crumbles into mixtures of gravel-sized particles known as grus that further may break down to produce a mixture of clay and silica sand or silt ...
Silicate minerals are rarely sufficiently valuable to warrant extraction as ore. However, some anorthosite intrusions contain such pure anorthite concentrations that they are mined for feldspar , for use in refractories , glassmaking, semiconductors and other sundry uses ( toothpaste , cosmetics , etc.).
A silicate mineral is generally an inorganic compound consisting of subunits with the formula [SiO 2+n] 2n−. Although depicted as such, the description of silicates as anions is a simplification. Balancing the charges of the silicate anions are metal cations, M x+. Typical cations are Mg 2+, Fe 2+, and Na +. The Si-O-M linkage between the ...