Calcite
Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/14730981@N08">James Petts</a> from London, England (CC BY-SA 2.0)
Mineral NameCalcite
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageperfect rhombohedral in three directions
Fractureconchoidal
Specific Gravity2.71
Colorswhite, yellowish-white
Transparencytranslucent
Type LocalityCardiff
Mineral GroupCarbonates
Usesconstruction, agriculture, optical, chemical industry, collector
Associated Mineralsquartz, fluorite, barite, pyrite, galena
Raritycommon
Description
A yellowish-white, translucent specimen of calcite, exhibiting prominent rhombohedral cleavage planes and a somewhat blocky habit.
Geological Context
Calcite is a ubiquitous mineral, forming in diverse geological settings including sedimentary rocks (limestone), metamorphic rocks (marble), hydrothermal veins, and as a secondary mineral in igneous rocks. It precipitates from calcium-rich aqueous solutions.
