aragonite

Aragonite is a carbonate mineral, one of the two common, naturally occurring polymorphs of calcium carbonate, CaCO3. The other is the mineral calcite. Aragonite's crystal lattice differs from that of calcite, resulting in a different crystal shape, an orthorhombic system with acicular crystals. Repeated twinning results in pseudo-hexagonal forms. Aragonite may be columnar or fibrous, occasionally in branching stalactitic forms called flos-ferri ("flowers of iron") from their association with the ores at the Carthinian iron mines. The type location for aragonite is Molina de Aragón (Guadalajara, Spain), 25 km outside Aragon. An aragonite cave, the Ochtinská Aragonite Cave, is situated in Slovakia. In the USA, stalactitic aragonite is known from Carlsbad Caverns. Massive deposits of oolitic aragonite are found on the seabed in the Bahamas.
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Noun
1. a mineral form of crystalline calcium carbonate; dimorphic with calcite
(hypernym) mineral

n. aragonite

(n.)
A mineral identical in composition with calcite or carbonate of lime, but differing from it in its crystalline form and some of its physical characters.
  

General Information:
 Chemical Formula:
CaCO3
 Composition:
(Molecular Weight = 100.09 gm)
Calcium 40.04 % Ca
Carbon 12.00 % C 
Oxygen 47.96 % O 
 Empirical Formula:
Ca(CO3)
 IMA Status:
Approved IMA 1963
 Locality:
Aragon (Spain).
 Name Origin:
Named after its locality.
Physical Properties:
 Cleavage:
[010] Distinct
 Color:
colorless, white, gray, yellowish white, or reddish white.
 Density:
2.93
 Diaphaniety:
Transparent to translucent
 Habits:
Pseudo Hexagonal - Crystals show a hexagonal outline., Columnar - Forms columns, Fibrous - Crystals made up of fibers.
 Hardness:
3.5-4 - Copper Penny-Flourite
 Luminescence:
None.
 Luster:
Vitreous (Glassy)
 Streak:
white
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