mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Hardness: 3 on Mohs scale; Color: Pale blue to sky blue; Luster: Vitreous to waxy; Crystal structure: Trigonal (often found as massive or rhombohedral); Cleavage: Perfect rhombohedral in three directions; Specific gravity: 2.71

Hardness: 3 on Mohs scale
Color: Pale blue to sky blue
Luster: Vitreous to waxy

Identified April 13, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed through sedimentary processes or igneous crystallization in hydrothermal veins. Large deposits are typically found in limestone and marble structures, often dating back to the Carboniferous or Jurassic periods depending on the specific deposit.

Uses & applications

Primarily used for ornamental purposes, carvings, jewelry (as cabochons), and as a popular specimen for crystal collecting and metaphysical practices.

Geological facts

Blue calcite is one of the most common carbonate minerals. It is known for its high birefringence (double refraction), though this is harder to see in the opaque blue variety compared to clear 'Iceland Spar' calcite.

Field identification & locations

Identify in the field by its distinct sky-blue color and softness (can be scratched by a copper penny or steel knife). It will react and effervesce (fizz) when exposed to cold dilute hydrochloric acid. Common locations include Mexico, Madagascar, and Brazil.