mineral

Aragonite Star Cluster

Aragonite (Calcium Carbonate, CaCO3)

Hardness: 3.5-4 (Mohs); Color: Honey-yellow to reddish-brown; Luster: Vitreous to resinous; Crystal structure: Orthorhombic, often forming pseudo-hexagonal twinned crystals; Cleavage: Distinct in one direction; Specific gravity: 2.95.

Hardness: 3
Color: Honey-yellow to reddish-brown
Luster: Vitreous to resinous

Identified March 20, 2026More mineral →

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Physical properties

Formation & geological history

Formed at low temperatures near the Earth's surface in sedimentary environments, often through precipitation from hydrothermal solutions or in evaporate deposits. This specific twinned morphology is commonly found in Morocco.

Uses & applications

Primarily used as decorative mineral specimens for collectors, in metaphysical practices, and occasionally as a source of lime for cement or soil pH balancing.

Geological facts

Aragonite is chemically identical to calcite (polymorphs), but they have different crystal structures. It is naturally unstable at standard surface temperatures and pressures, eventually recrystallizing into calcite over geological timescales.

Field identification & locations

Identify in the field by its distinct 'star' or radiating hexagonal prism clusters and its reaction (fizzing) when exposed to cold dilute hydrochloric acid. Common locations include Tazouta, Morocco, and Aragon, Spain.

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