mineral

Aragonite cluster

Aragonite, CaCO₃ (orthorhombic polymorph of calcite)

AI-generated identification · may be incorrect

Honey-brown to tan, translucent crystals with vitreous to pearly luster; hardness 3.5–4 Mohs, specific gravity about 2.94, commonly radiating or pseudo-hexagonal twin clusters with imperfect cleavage.

Identified August 21, 2026More mineral →

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Physical properties

Formation & geological history

Forms at low temperatures in caves, hot springs, evaporite deposits, and marine or biological settings through precipitation of calcium carbonate. Individual specimens may form in relatively young deposits, including modern cave and hydrothermal environments.

Uses & applications

Used mainly as a collector specimen, ornamental stone, and minor carbonate raw material; it is not generally suitable for jewelry because of low hardness and cleavage.

Geological facts

Aragonite is metastable at Earth’s surface and may slowly recrystallize into calcite. The distinctive clustered, radiating crystal habit helps distinguish it from ordinary calcite.

Field identification & locations

Identify by its radiating clustered crystals, brown coloration, moderate hardness, and lack of reaction distinction from calcite: both effervesce strongly in dilute hydrochloric acid. Common localities include Spain, Morocco, Mexico, Austria, and cave deposits worldwide.