Minerals

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General Information

Aragonite

Aragonite is one of the two natural calcium carbonate minerals. (The other one is calcite.) Aragonite grows in the form of pillars or needles. Aragonite is formed at low temperatures and can therefore be found in caves, hot springs, shellfish shells or as oolites on the bottom of shallow seas.[1]

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Chemical & Physical Information

Trivial NameAragonite
Chemical NameCalcium Carbonate
Chemical FormulaCaCO3
Density2,94 g·cm-3
Molar mass?
Hardness3,5-4
Crytal systemOrthorombic and hexagonal
Unit cell?
Crystal habit?
FractureConchoidal
CleavageDistinct on [010]
ColourWhite, red, yellow, orange, green, bleu and brown.
LusterGlass, dull
StreakWhite
OpacityTransparent to translucent.
SafetySafe
ExtraTurns into calcite due to thermodynamic instability.
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Photos

Aragonite

(2 cm)

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Sources

[1] Wikipedia

[2] Specimen from my personal collection, photo taken by me.