Blue Calcite

Physical Properties

Hardness: 3 on Mohs scale; Color: Pale blue to sky blue; Luster: Vitreous to pearly; Crystal structure: Trigonal/Rhombohedral; Cleavage: Perfect rhombohedral in three directions; Specific gravity: 2.71.

Formation & Geological History

Formed through sedimentary processes, often by chemical precipitation in marine environments or through hydrothermal activity. It is common in limestone and marble formations of various geological ages.

Uses & Applications

Used primarily as decorative carvings, lapidary slabs, and as a popular specimen for metaphysical and mineral collectors. Industrial uses of calcite include cement, lime, and as a soil neutralizer.

Geological Facts

Blue calcite is particularly known for its 'waxy' texture when handled. It is acid-sensitive and will effervesce (fizz) if a drop of weak hydrochloric acid or vinegar is applied to it.

Field Identification & Locations

Identify by its softness (can be scratched by a copper penny) and its distinct rhombohedral cleavage. Commonly found in Madagascar, Mexico, and Brazil. Collectors look for deep color and translucency.

Identified on: 4/30/2026

Mode: Standard