mineral
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Hardness: 7 (Mohs scale), Color: White to yellowish-tan, Luster: Vitreous to waxy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 (Mohs scale), Color: White to yellowish-tan, Luster: Vitreous to waxy, Crystal structure: Trigonal/Hexagonal, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed in hydrothermal veins or pegmatites from silica-rich solutions settling in rock fractures. Its cloudy appearance is caused by tiny inclusions of gas or liquid trapped during crystal growth.
Uses & applications
Used in glassmaking, construction aggregates, jewelry, as a source for silicon metal, and in electronics for its piezoelectric properties.
Geological facts
Quartz is the second most abundant mineral in Earth's crust. Its name comes from the German word 'quarz', which originally meant 'hard'. The milky appearance is due to millions of fluid inclusions.
Field identification & locations
The provided coordinates near Sao Paulo, Brazil, are within the crystalline basement of the Mantiqueira Province, where quartz-rich pegmatites and metamorphic rocks are extremely common. Identify by its ability to scratch glass and lack of cleavage.
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