mineral

Aragonite Star Cluster

Aragonite (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3.5-4.0; Color: Honey-orange to reddish-brown; Luster: Vitreous to resinous; Crystal Structure: Orthorhombic (often forming hexagonal-looking pseudohexagonal twins); Specific Gravity: 2.95

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

Identified July 18, 2026More mineral →

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Physical properties

Hardness: 3.5-4.0; Color: Honey-orange to reddish-brown; Luster: Vitreous to resinous; Crystal Structure: Orthorhombic (often forming hexagonal-looking pseudohexagonal twins); Specific Gravity: 2.95

Formation & geological history

Formed in low-temperature near-surface environments, often as an authigenic mineral in sedimentary rocks or through precipitation in hot springs and caves, typically within the last few million years.

Uses & applications

Primarily used as a decorative mineral specimen for collectors, sometimes used in metaphysical practices, and historically as a minor source of lime.

Geological facts

Aragonite is a polymorph of Calcite, meaning they share the same chemistry but different crystal structures. It is also the primary constituent of mother-of-pearl (nacre) in mollusk shells.

Field identification & locations

Identified by its distinctive twinned, radiating hexagonal prisms (star clusters) and its reaction (fizzing) with weak hydrochloric acid. Famous specimens come from Tazouta, Morocco.