Aragonite
Real mineral · common · CaCO₃
A polymorph of calcite that forms at lower temperatures and higher pressures. Metastable at surface conditions and slowly converts to calcite over geological time. The main component of mollusk shells and coral skeletons.
Identity
- Formula
- CaCO₃
- Chemical class
- carbonate
- Mineral group
- Cerussite
- Also known as
- Flos ferri (cave variety), Frutillar spar
Crystallography
- Crystal system
- orthorhombic
- Habits
- prismatic, tabular, acicular, massive
- Fracture
- subconchoidal
Physical properties
- Mohs hardness
- 3.5
- Density
- 2.93 g/cm³
- Luster
- vitreous, resinous
- Colors
- colorless, white, yellow, pink, brown
- Streak
- white
- Transparency
- transparent, translucent
Geology
- Origins
- sedimentary, hydrothermal
- Host rocks
- limestone, cave deposits, coral
- Associated minerals
- Calcite, Gypsum, Sulfur, zeolite
- Geography
- worldwide
Classification
- Rarity
- common
- Gem quality
- No
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