mineral
Aragonite
Aragonite (CaCO3)
AI-generated identification · may be incorrectHardness: 3.5-4 (Mohs), Color: Colorless, white, yellow, or pale brown, Luster: Vitreous to resinous, Crystal Structure: Orthorhombic, Cleavage: Distinct in one direction, Specific Gravity: 2.95
- Hardness
- 3
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: Colorless, white, yellow, or pale brown, Luster: Vitreous to resinous, Crystal Structure: Orthorhombic, Cleavage: Distinct in one direction, Specific Gravity: 2.95
Formation & geological history
Forms in low-temperature environments near the Earth's surface, such as in hot springs, caves as stalactites, and as the shells of marine organisms like mollusks and corals.
Uses & applications
Used primarily as a collector's specimen and in some jewelry; it is also an important component in reef aquariums to maintain calcium levels.
Geological facts
Aragonite is chemically identical to calcite but has a different crystal structure, making them polymorphs. Most modern corals and pearl-bearing mollusks secrete aragonite for their skeletal structures.
Field identification & locations
Identified by its reaction to dilute hydrochloric acid (effervescence) and its pseudo-hexagonal crystal habits. Found commonly in sedimentary environments and limestone caves globally.
