Calcite, calcite, calcspar or double spar, is a very frequently occurring mineral from the mineral class of "carbonates and nitrates" with the chemical composition Ca[CO3] and thus chemically seen calcium carbonate.
Calcite crystallizes in the trigonal crystal system and develops different crystal or aggregate forms (habitus). In its pure form calcite is colourless and transparent. Due to multiple refraction of light due to lattice defects or polycrystalline formation, calcite can also appear white, with a corresponding decrease in transparency, and can take on a yellow, pink, red, blue, green, brown or black color through foreign admixtures.
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