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Arsenopyrite in older literature may be referred to as mispickel, a name of German origin. [6] It is also sometimes referred to as mundic, a word derived from Cornish dialect and which also refers to a copper ore, as well as a form of deterioration in aggregate concrete made with mine tailings.
Phenocrysts of clear glassy rounded quartz and white orthoclase feldspar are set in a fine-grained matrix. Sample is just over 10 cm long Sample is just over 10 cm long Quartz-porphyry , in layman's terms, is a type of volcanic ( igneous ) rock containing large porphyritic crystals of quartz .
The grey and white crystals are quartz and (limited) feldspar. Metamorphism is the transformation of existing rock (the protolith ) to rock with a different mineral composition or texture . Metamorphism takes place at temperatures in excess of 150 °C (300 °F), and often also at elevated pressure or in the presence of chemically active fluids ...
Orthoclase, or orthoclase feldspar (endmember formula K Al Si 3 O 8), is an important tectosilicate mineral which forms igneous rock. The name is from the Ancient Greek for "straight fracture", because its two cleavage planes are at right angles to each other.
Often the species of mafic minerals is included in the name, for instance, hornblende-bearing granite, pyroxene tonalite or augite megacrystic monzonite, because the term "granite" already assumes content with feldspar and quartz. The rock texture thus determines the basic name of a felsic rock. Close-up of granite from Yosemite National Park.
Goldstone showing aventurescence. In gemology, aventurescence (sometimes called aventurization) is an optical reflectance effect seen in certain gems.The effect amounts to a metallic glitter, arising from minute, preferentially oriented mineral platelets within the material.
This is a list of countries by feldspar production in 2019 based on British Geological Survey data. [1] Feldspar production (tonnes) by country Rank Country
The distinctive character of feldspar in hypersolvus granite is to present exsolution textures. That is because the high temperature feldspar was ternary (i.e. contained comparable parts of the Ca, Na, K components) and was later dissociated during the cooling phase into K-rich parts and Na-Ca-rich parts, within the initial crystal.