mineral
Aragonite Star Cluster
Aragonite (CaCO3)
AI-generated identification · may be incorrectHardness: 3.5-4 on Mohs scale; Color: Reddish-brown, orange, white; Luster: Vitreous to resinous; Crystal structure: Orthorhombic (often forming pseudo-hexagonal twinned prisms); Cleavage: Distinct in one direction.
- Hardness
- 3
- Color
- Reddish-brown, orange, white
- Luster
- Vitreous to resinous
Identified More mineral →
Explore Aragonite Star Cluster in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5-4 on Mohs scale; Color: Reddish-brown, orange, white; Luster: Vitreous to resinous; Crystal structure: Orthorhombic (often forming pseudo-hexagonal twinned prisms); Cleavage: Distinct in one direction.
Formation & geological history
Formed at low temperatures near the Earth's surface in oxidized zones of ore deposits, hot springs, or sedimentary environments. These specific 'sputnik' clusters typically form in clay-rich soils via twinning.
Uses & applications
Primarily used as decorative display specimens for collectors and in metaphysical practices. Scientifically important for understanding ocean acidification effects on calcifying organisms.
Geological facts
Aragonite is a polymorph of Calcite, meaning they share the same chemical formula but different crystal systems. Over geological time, aragonite often reverts to the more stable calcite structure.
Field identification & locations
Identify by its distinctive twinned hexagonal prisms radiating from a central point. Most 'star' specimens come from the Molina de Arag3n region in Spain or regions in Morocco. It will effervesce (fizz) in contact with dilute hydrochloric acid.
