mineral
Aragonite
Aragonite (Calcium Carbonate - CaCO3)
AI-generated identification · may be incorrectHardness: 3.5-4 (Mohs); Color: White, yellow, gold, brown; Luster: Vitreous to resinous; Crystal structure: Orthorhombic; Cleavage: Distinct in one direction; Specific gravity: 2.95.
- Hardness
- 3
- Color
- White, yellow, gold, brown
- Luster
- Vitreous to resinous
Identified More mineral →
Explore Aragonite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5-4 (Mohs); Color: White, yellow, gold, brown; Luster: Vitreous to resinous; Crystal structure: Orthorhombic; Cleavage: Distinct in one direction; Specific gravity: 2.95.
Formation & geological history
Forms by biological and physical processes in marine and freshwater environments as shells or pearls. Also forms as precipitates in hot springs, karst caves, and some metamorphic rocks through low-temperature hydrothermal activity.
Uses & applications
Used primarily as decorative carvings, ornamental stones, jewelry beads, and as a calcium supplement in aquarium reef-building.
Geological facts
Aragonite is a polymorph of Calcite, meaning it has the same chemical formula but a different crystal structure. It is the primary component of most mollusk shells and the pearly layer of nacre.
Field identification & locations
Identify in the field by checking for its characteristic 'sputnik' or needle-like crystal habit and its reaction (effervescence) to weak acid. Common in Spain, Morocco, Mexico, and the USA.
