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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 ...
The Nickel–Strunz classifications are 9.F (tectosilicates without zeolitic H 2 O), 9.G (tectosilicates with zeolitic H 2 O), and 4.DA (quartz/silica group). Below is a list of tectosilicate minerals and their chemical formulas, organized by groups and series: Quartz group Quartz – SiO 2; Tridymite – SiO 2; Cristobalite – SiO 2; Coesite ...
Mineral symbols (text abbreviations) are used to abbreviate mineral groups, subgroups, and species, just as lettered symbols are used for the chemical elements. The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [ 1 ]
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.
In order for a rock (rather than a mineral) to be classified as felsic, it generally needs to contain more than 75% felsic minerals (namely quartz, orthoclase and plagioclase). Rocks with greater than 90% felsic minerals can also be called leucocratic , [ 4 ] from the Greek words for white and dominance.
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 ...
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.
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 ...