Answers

2015-01-17T23:16:09+05:30
It is actually a hard mineral consisting of silica, found widely in igneous and metamorphic rocks.
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2015-01-17T23:18:58+05:30
A very hard mineral composed of silica, SiO2, found worldwide in many different types ofrocks, including sandstone and granite. Varieties of quartz include agate, chalcedony, chert,flint, opal, and rock crystal.
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