mineral

Aragonite crystal cluster

Aragonite, orthorhombic CaCO₃

AI-generated identification · may be incorrect

Typically white to colorless, translucent, vitreous to pearly, with radiating acicular or branching crystals; Mohs hardness 3.5–4, imperfect cleavage, and specific gravity about 2.94. The specimen appears to be a large, pale aragonite “flos ferri” or coral-like cluster, possibly displayed as a museum specimen.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Aragonite forms at low temperatures in caves, hydrothermal veins, evaporite settings, and marine environments; branching clusters commonly develop in caves or mineral deposits. It is geologically young to modern in many occurrences, though individual deposits can be much older.

Uses & applications

Used mainly for mineral collecting, museum display, and educational purposes; fine transparent crystals may be used as decorative specimens, but it is too soft and unstable for most jewelry.

Geological facts

Aragonite is a polymorph of calcite: both have CaCO₃ but different crystal structures. It can slowly alter to calcite over geological time, especially under ordinary surface conditions.

Field identification & locations

Identify it by its radiating needle-like branching habit, relatively low hardness, and reaction with dilute hydrochloric acid; calcite is softer and typically forms different crystal shapes. Notable localities include Morocco, Spain, Austria, Mexico, and cave deposits worldwide.