mineral

Aragonite Star Cluster

Aragonite (Calcium Carbonate - CaCO3)

Hardness: 3.5-4.0; Color: Honey-brown, reddish-brown, or orange; Luster: Vitreous to resinous; Crystal structure: Orthorhombic (specifically pseudo-hexagonal twinning); Cleavage: Distinct; Specific gravity: 2.95

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

Identified March 15, 2026More mineral →

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Physical properties

Formation & geological history

Formed through low-temperature hydrothermal activity or as a secondary mineral in the oxidized zones of ore deposits. These specific 'Sputnik' or 'Star' clusters are most famously found in sedimentary clay beds in Morocco.

Uses & applications

Primarily used as decorative display specimens for collectors and in metaphysical practices. Industrially, aragonite is used in cement, soil pH balancing, and aquarium substrates.

Geological facts

Aragonite is chemically identical to calcite but has a different crystal structure, making them polymorphs. Over long geological periods, aragonite often recrystallizes into the more stable calcite. It is also the primary material found in mother-of-pearl and pearls.

Field identification & locations

Identify by its distinctive six-sided prism 'twinned' crystals radiating from a central point. Common locations include Tazouta, Morocco; Molina de Aragón, Spain (the type locality); and various locations in Sicily and Namibia.

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