Calcite
Image: Didier Descouens (CC BY-SA 3.0)
Mineral NameCalcite
Chemical FormulaCaCO₃
Mohs Hardness3
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageperfect rhombohedral in three directions
Fractureconchoidal to uneven
Specific Gravity2.71
Colorspale yellow, white, cream, blue (fluorescent)
Transparencytransparent to translucent
Type LocalitySouth Morocco
Mineral GroupCarbonates
Usesconstruction, industrial, optical, collector, agricultural
Associated Mineralsquartz, fluorite, barite, sulfides
Raritycommon
Description
This specimen features a cluster of pointed, dogtooth-like calcite crystals within a vug. In daylight, the crystals are a pale yellowish-white, and under ultraviolet light, they exhibit a striking bright blue fluorescence.
Geological Context
Calcite is a ubiquitous mineral found in diverse geological settings, including sedimentary rocks (limestone, marble), hydrothermal veins, and cave formations. It precipitates from calcium-rich solutions in various environments.
