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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 ...
Skarn type mineralisation related to these granites is a very important type of tin, tungsten, and molybdenum deposit. Skarn deposits form by reaction of mineralised fluids from the granite reacting with wall rocks such as limestone. Skarn mineralisation is also important in lead, zinc, copper, gold, and occasionally uranium mineralisation.
Stone industry refers to the part of the primary sector of the economy, similar to the mining industry, but concerned with excavations of stones, in particular granite, marble, slate and sandstone. Other products of the industry include crushed stone and dimension stone. Stone industry is one of the oldest in the world.
Mineral economics is the academic discipline that investigates and promotes understanding of economic and policy issues associated with the production and use of mineral commodities. [ 1 ] Mineral economics [′min·rəl ‚ek·ə′näm·iks] is specially concerned with the analysis and understanding of mineral distribution as well as the ...
Economic geology is concerned with earth materials that can be used for economic and industrial purposes. These materials include precious and base metals, nonmetallic minerals and construction-grade stone. Economic geology is a subdiscipline of the geosciences; according to Lindgren (1933) it is “the application of geology”.
Sulfide mineral cumulates in layered intrusions are an important source of nickel, copper, platinum group elements and cobalt. Deposits of a mixed massive or mixed sulfide-silicate 'matrix' of pentlandite , chalcopyrite , pyrrhotite and/or pyrite are formed, occasionally with cobaltite and platinum-tellurium sulfides.
Silica content is thus the most important chemical criterion for classifying igneous rock. [7] The content of alkali metal oxides is next in importance. [11] About 65% of the Earth's crust by volume consists of igneous rocks. Of these, 66% are basalt and gabbro, 16% are granite, and 17% granodiorite and diorite.
Granite requires a water content of 4 wt% at a pressure of 0.5 GPa (72,500 psi), but only 1.5 wt% at 0.1 GPa (14,500 psi) for phase separation to take place. [ 14 ] The volatiles (primarily water, borates , fluorides , chlorides , and phosphates ) are concentrated in the hydrous phase, greatly lowering its viscosity. [ 5 ]