Rocks or minerals lacking crystal structure or form
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Tag: <span>A</span>
A variety of translucent to transparent purple to grey coloured quartz common as a semiprecious gemstone. The color results from with ferric iron substitution for silicon
The surrounding or encompassing and current state of an area
The formation of usually fossilized amorphous hydrocarbons from ancient tree resins, having highly variable C:H:O ratios
A bright green or blue green variety of microcline sometimes cut as semi precious stones and for ornamental use
Alloys of mercury with one or more metal
A light, silvery-white, ductile metal with high electrical conductivity and high resistance to oxidation. Symbol, Al
Physical and chemical changes in a rocks or mineral subsequent to initial formation, and to a lesser degree than metamorphosis
A corrosive, noxious, yellow liquid made with nitric and hydrochloric acids, usually one part nitric acid and three parts hydrochloric acid. Used in efficiently dissolving and processing gold and platinum
A type of grey to black volcanic rock composed mostly of silica, plus iron and magnesium