mineral

Milky calcite

Calcite (calcium carbonate, CaCO₃)

AI-generated identification · may be incorrect

White to translucent, vitreous-to-pearly luster, commonly showing rhombohedral cleavage and blocky forms; Mohs hardness 3, specific gravity about 2.71. The apparent planar cleavage and soft, glassy appearance fit calcite better than quartz.

Identified August 29, 2026More mineral →

Explore Milky calcite in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Formation & geological history

Forms from precipitation in limestone, caves, hydrothermal veins, and sedimentary environments; deposits range from ancient to modern, with age dependent on its host formation.

Uses & applications

Used for cement, lime, aggregate, soil treatment, and chemical manufacture; clear specimens are collected, though this piece appears to be a common rough specimen.

Geological facts

Calcite strongly effervesces with dilute hydrochloric acid, unlike quartz; it also exhibits birefringence, producing doubled images when viewed through a clear crystal.

Field identification & locations

Common worldwide, especially in limestone regions, hydrothermal veins, and caves. Confirm with a steel knife or copper coin scratch test and a tiny acid drop on an inconspicuous area; do not confuse with gypsum, which is softer and often fibrous.