mineral

Aragonite

Aragonite (Calcium Carbonate - CaCO3)

Hardness: 3.5-4 (Mohs scale), Color: Amber, white, or colorless, Luster: Vitreous to resinous, Crystal system: Orthorhombic, Cleavage: Poor, Specific Gravity: 2.9-3.0

Hardness: 3

Identified May 26, 2026More mineral →

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Physical properties

Hardness: 3.5-4 (Mohs scale), Color: Amber, white, or colorless, Luster: Vitreous to resinous, Crystal system: Orthorhombic, Cleavage: Poor, Specific Gravity: 2.9-3.0

Formation & geological history

Formed through biological and physical processes in marine and freshwater environments, as well as in caves as stalactites or near hot springs through precipitation from calcium-rich waters.

Uses & applications

Used primarily as decorative specimens, in jewelry (especially 'Sputnik' crystals), and occasionally in soil conditioners and the manufacturing of glass or cement.

Geological facts

Aragonite is chemically identical to calcite but has a different crystal structure, making them polymorphs. Most mollusk shells and pearls are made of aragonite.

Field identification & locations

Identify by its unique crystal habits (often hexagonal-looking or acicular) and check for effervescence when exposed to dilute hydrochloric acid. Commonly found in Spain, Morocco, and the USA.