Calcite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameCalcite
Chemical FormulaCaCO3
Mohs Hardness3
Crystal Systemtrigonal
Streak ColorWhite
CleavagePerfect rhombohedral in three directions
FractureConchoidal to uneven
Specific Gravity2.71
Colorsyellowish-white, colorless
TransparencyTranslucent
Type LocalityIdar-Oberstein, Hunsrück Mts, Rhineland-Palatinate, Germany
Mineral GroupCarbonates
Usesindustrial, optical, collector
Associated MineralsAmethyst
Raritycommon
Description
A cluster of translucent, yellowish-white calcite crystals with blocky forms, growing prominently on a matrix of dark purple amethyst crystals.
Geological Context
Calcite commonly forms in hydrothermal veins and vugs, often precipitating as a later-stage mineral on pre-existing quartz or amethyst in volcanic environments, such as those found in the Idar-Oberstein region.
