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2. Quartz - Wikipedia

   en.wikipedia.org/wiki/Quartz

   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. [10] Quartz exists in two forms, the normal α-quartz and the high-temperature β-quartz, both of which are chiral. The transformation ...

3. Tourmaline - Wikipedia

   en.wikipedia.org/wiki/Tourmaline

   Tri-chromatic elbaite crystals on quartz, Himalaya Mine, San Diego Co., California, US Tourmaline is a six-member ring cyclosilicate having a trigonal crystal system. It occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section, often with curved striated faces.

4. Smoky quartz - Wikipedia

   en.wikipedia.org/wiki/Smoky_quartz

   Smoky quartz is a brownish grey, translucent variety of quartz that ranges in clarity from almost complete transparency to an almost-opaque brownish-gray or black crystals. [6] The color of smoky quartz is produced when natural radiation, emitted from the surrounding rock, activates color centers around aluminum impurities within the ...

5. Pegmatite - Wikipedia

   en.wikipedia.org/wiki/Pegmatite

   Quartz crystals with masses measured in thousands of pounds [5] and micas over 10 meters (33 ft) across and 4 meters (13 ft) thick have been found. [8] Spodumene crystals over 12 meters (40 ft) long have been found in the Black Hills of South Dakota , and beryl crystals 8.2 meters (27 ft) long and 1.8 meters (6 ft) in diameter have been found ...

6. Mineral alteration - Wikipedia

   en.wikipedia.org/wiki/Mineral_alteration

   Mineral alteration refers to the various natural processes that alter a mineral's chemical composition or crystallography. [1]Mineral alteration is essentially governed by the laws of thermodynamics related to energy conservation, relevant to environmental conditions, often in presence of catalysts, the most common and influential being water (H 2 O).

7. Quartz fiber - Wikipedia

   en.wikipedia.org/wiki/Quartz_fiber

   A quartz fiber dosimeter, a device using a quartz fiber.. Since quartz fiber is expensive, it has limited applications. [2] It is used mainly for producing composite materials (due to having higher stability compared to glass fiber) and in electrical applications where thermal resistance and dielectric properties are important. [9]