mineral

Calcite

Calcite (CaCO₃), likely honey/yellow calcite

AI-generated identification · may be incorrect

Usually Mohs hardness 3; pale yellow to cream, vitreous to pearly luster, translucent, and commonly rhombohedral cleavage. The specimen appears massive and irregular, with possible iron staining and a small blue surface inclusion or coating.

Identified September 6, 2026More mineral →

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Physical properties

Formation & geological history

Forms in limestone, marble, hydrothermal veins, caves, and evaporite environments through precipitation or recrystallization. Calcite occurs from Precambrian to Recent ages and is widespread globally.

Uses & applications

Used to manufacture cement, lime, and agricultural soil additives; clear optical calcite is collected, while attractive honey calcite is used as a lapidary and display material.

Geological facts

Calcite effervesces vigorously with dilute hydrochloric acid or vinegar, unlike quartz. It shows strong double refraction in clear pieces and is a principal mineral of limestone.

Field identification & locations

Identify it by its softness, rhombohedral cleavage, and acid reaction; a copper coin or steel blade can scratch it. Common localities include Mexico, Iceland, the United States, China, and Morocco.