mineral
Calcite (Optical or Clear Calcite)
Calcium Carbonate (CaCO3)
AI-generated identification · may be incorrectHardness: 3 on Mohs scale; Color: Clear to white; Luster: Vitreous/Glassy; Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71
- Hardness
- 3 on Mohs scale
- Color
- Clear to white
- Luster
- Vitreous/Glassy
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Physical properties
Hardness: 3 on Mohs scale; Color: Clear to white; Luster: Vitreous/Glassy; Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific Gravity: 2.71
Formation & geological history
Formed through chemical precipitation in sedimentary environments, hydrothermal veins, or as a primary mineral in igneous carbonatites. It is often found in limestone and marble deposits.
Uses & applications
Used in the manufacture of cement and mortar, as a soil conditioner in agriculture, in the optical industry (for polarizing prisms), and as a decorative collector specimen.
Geological facts
Calcite exhibits double refraction (birefringence); if you place a clear piece over text, the letters appear doubled. It is the primary constituent of stalactites and stalagmites in caves.
Field identification & locations
Identify in the field using a 'fizz test' with dilute hydrochloric acid; it will effervesce vigorously. Look for the characteristic rhombohedral 'leaning box' shape and low hardness (can be scratched by a copper penny).
