mineral
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
AI-generated identification · may be incorrectHardness: 3.5-4 (Mohs scale); Color: reddish-brown or honey; Luster: Vitreous to resinous; Crystal structure: Orthorhombic (often forming pseudo-hexagonal twinned crystals); Specific gravity: 2.9-3.0.
- Hardness
- 3
- Color
- reddish-brown or honey
- Luster
- Vitreous to resinous
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Physical properties
Hardness: 3.5-4 (Mohs scale); Color: reddish-brown or honey; Luster: Vitreous to resinous; Crystal structure: Orthorhombic (often forming pseudo-hexagonal twinned crystals); Specific gravity: 2.9-3.0.
Formation & geological history
Formed primarily through sedimentary processes in oxidation zones of ore deposits, caves, or hot springs. These characteristic 'star' clusters are typically from the Tazouta mine in Morocco, formed by cyclic twinning of crystals.
Uses & applications
Primarily popular as a display cabinet specimen for mineral collectors. Some lower grade material is used for ornamental carvings or as a source of calcium, but it is too soft for most jewelry.
Geological facts
Aragonite is chemically identical to Calcite but has a different crystal structure, making them polymorphs. Over long geological time, aragonite often reverts to the more stable calcite form.
Field identification & locations
Identified by its standard pseudo-hexagonal twinned prisms and distinctive reddish-brown color. Found commonly in Morocco, Spain, and Mexico. Collectors should avoid cleaning with acid as it will dissolve.
