Blue Calcite

Physical Properties

Hardness: 3 on Mohs scale. Color: Pale blue to sky blue. Luster: Vitreous to waxy. 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 from calcium-rich solutions or the accumulation of shell, coral, and algal debris. It can also form in hydrothermal veins or metamorphic environments (marble).

Uses & Applications

Predominantly used as a decorative stone, in lapidary work for carvings, and as a popular 'healing' crystal in metaphysical practices. Industrial calcite is used in cement, antacids, and as a fertilizer.

Geological Facts

Calcite is one of the most common minerals on Earth and is the primary constituent of limestone and marble. The blue variety is particularly prized for its soothing aesthetic and is often found in large, rhombohedral 'cleavage rhombs'.

Field Identification & Locations

Identify in the field by its 3-direction rhombohedral cleavage (it breaks into tilted cubes/blocks) and its reaction to dilute hydrochloric acid (it will effervesce/fizz). It is soft enough to be scratched by a copper penny or a steel knife.

Identified on: 4/13/2026

Mode: Standard