Orthorhombic polymorph of calcium carbonate, less stable than calcite. Forms in biological systems shells, pearls and cave deposits. Color: White, yellow, blue, green. Luster: Vitreous. Streak: White. Cleavage: Poor. Hardness: 3.5-4. Transparency: Transparent to translucent. Crystal system: Orthorhombic. Chemical formula: CaCO₃. Specific gravity: 2.94. Formation: Precipitates from warm seawater, forms in hot springs travertine , and is secreted by mollusks for shells. Common geological settings: Spain, Morocco, Namibia, USA; found in hot spring deposits and as biogenic mineral. Common look-alikes and related entries: Calcite, Witherite, Strontianite.
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
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GeoMiner
Last updated
2026-03-30T14:37:01.47627+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Orthorhombic polymorph of calcium carbonate, less stable than calcite. Forms in biological systems shells, pearls and cave deposits.
How can you identify Aragonite?
Compare several properties rather than relying on colour alone. This entry records colour: White, yellow, blue, green; lustre: Vitreous; streak: White; Mohs hardness: 3.5-4; cleavage: Poor; crystal system: Orthorhombic; transparency: Transparent to translucent. Confirm an important identification with additional field tests or qualified laboratory work.
How does Aragonite form?
Precipitates from warm seawater, forms in hot springs travertine , and is secreted by mollusks for shells.
Where is Aragonite commonly found?
Spain, Morocco, Namibia, USA; found in hot spring deposits and as biogenic mineral.
What is Aragonite commonly confused with?
Aragonite may be confused with Calcite, Witherite, Strontianite. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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