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Quartz is, therefore, classified structurally as a framework silicate mineral and compositionally as an oxide mineral. Quartz is the second most abundant mineral in Earth's continental crust, behind feldspar. [9] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...
Dynamic quartz recrystallization happens in a relatively predictable way with relation to temperature, and given its abundance quartz recrystallization can be used to easily determine relative temperature profiles, for example in orogenic belts or near intrusions.
For example, amethyst is a purple variety of the mineral species quartz. Some mineral species can have variable proportions of two or more chemical elements that occupy equivalent positions in the mineral's structure; for example, the formula of mackinawite is given as (Fe,Ni) 9 S 8, meaning Fe x Ni 9-x S 8, where x is a variable number between ...
Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock.
Phantom quartz is a variety of quartz consisting of visible layers of overlapping crystal growths. The outline of the inner crystals can be seen due to some variation in composition or mineral inclusion making the boundary between growths visible. [1] The interior crystal layers are known as phantoms. Phantoms can be found in many varieties of ...
Quartzolite or silexite is an intrusive igneous rock, in which the mineral quartz is more than 90% of the rock's felsic mineral content, with feldspar at up to 10%. [ 1 ] : 135 [ 2 ] Typically, quartz forms more than 60% of the rock, [ 3 ] the rest being mostly feldspar although minor amounts of mica or amphibole may also be present. [ 2 ]
In geology and mineralogy, a mineral variety is a subset of a mineral species or mineraloid with some special characteristic, such as specific impurities or structural defects. [1] For example, amethyst is a variety of quartz with a purple tinge due in part to iron impurities. Mineral varieties can be further subdivided into sub-varieties. [1]
Category for mines for quartz, a form of silicon dioxide, and the second most abundant mineral in the Earth's crust after feldspar (which itself makes up to 60% of the Earth's crust). See also Category:Quartzite caves