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Quartz is a mineral with skaloobrazuvasht chemical formula SiO2. There are pronounced piezoelectric properties. Hardness 7 on the Mohs scale.There are vodnobistar - rock crystal, white - milky quartz, violet - Amethyst, black - morion Yellow - citrine, smoky quartz - rauhtopaz and others. Vodnobistrite find application in optical piezokvartsat - in radio-electronics and others.; Beautifully colored and transparent - in jewelry. It is also used in the manufacture of watches.
