Blue Calcite

Physical Properties

Hardness: 3 on Mohs scale. Color: Pale blue to sky blue. Luster: Vitreous to waxy. Crystal Structure: Trigonal. Cleavage: Perfect rhombohedral. Specific Gravity: 2.71.

Formation & Geological History

Formed through sedimentary processes via chemical precipitation from calcium-rich solutions, or in metamorphic environments as a constituent of marble. It is found in deposits of varying geological ages.

Uses & Applications

Primarily used as a decorative stone, in lapidary work (cabochons, carvings), and as a specimen for mineral collectors. Industrial calcite is used in cement and acidity neutralization.

Geological Facts

Blue calcite is known for its relatively soft nature, making it popular for beginners to carve. It can double-refract light, a property known as birefringence, though this is more visible in clear 'Iceland Spar' varieties.

Field Identification & Locations

Identify in the field by its rhombohedral cleavage (it breaks into slanted cubes), its softness (can be scratched by a copper penny), and its effervescence when coming into contact with dilute hydrochloric acid. Commonly found in Madagascar and Mexico.

Identified on: 4/13/2026

Mode: Standard