Apr 30 2014
Calcite was named after a Latin word ‘calx’, meaning burnt lime, which is an allusion to one of its important commercial uses.
Properties of Calcite
The following are the key properties of calcite:
- Cell Data
- Space group: R3c
- a = 4.9896(2)
- c = 17.0610(11)
- Z = 6
- Crystal Data
- Hexagonal
- Point group: 3 2/m
- Well-formed crystals are common, {1011}, {2131}, thin to thick tabular {0001}, with combinations of over 1000 forms noted, to 7 m
- Granular, stalactitic, in concretions, massive
- Twinning: On {0112}, {1011}, {0001}, {0221} as twin and composition planes
- X-ray powder pattern: 3.035 (100), 2.285 (18), 2.095 (18), 1.913 (17), 1.875 (17), 2.495 (14), 3.86 (12)
- Chemical Composition
| Elements |
Content 1 |
Content 2 |
| CaO |
53.60 |
56.03 |
| CO2 |
[44.22] |
43.97 |
| MgO |
1.74 |
|
| FeO |
0.43 |
- |
| Total |
[99.99] |
100.00 |
- Optical Properties
- Optical class: Uniaxial (-); anomalously biaxial
- Absorption: O > E
- Dispersion: Very strong
- ω = 1.658
- ε = 1.486
- 2V(meas.) = 0° to small
- Estimated Properties
| Electron density |
Bulk density (electron density) = 2.71 g/cm3
note: Specific gravity of calcite = 2.71 g/cm3 |
| Photoelectric |
PECalcite = 5.06 barns/electron
U=PECalcite x ρ electron density= 13.70 barns/cm3 |
| Fermion index |
Fermion index = 0.0020908312
Boson index = 0.9979091688 |
Radioactivity
|
Calcite is not radioactive
|
How to Identify Calcite
Calcite can be identified in the field by its color variations, such as white, pink, yellow, and brown. It is sometimes colorless. Its transparent to translucent to opaque form has {1011} perfect, {1011} perfect, and {1011} perfect cleavage. This mineral has a vitreous luster with a white streak. The fracture on this mineral is brittle - conchoidal. The density of calcite is 2.71 g/cm3, with a hardness of 3 – approximate to calcite. It is fluorescent and phosphorescent.
Global Distribution
Calcite is distributed in the following places:
- Iceland - At the Helgustadanama mine, Reydarfjord
- England - From Alston Moor, Egremont, and Frizington, Cumbria; Weardale, Durham; at Liskeard, Cornwall
- Germany - From St. Andreasberg, Harz Mountains, and Freiberg, Saxony
- Namibia - From Tsumeb
- Congo - In the Mupine mine, Katanga Province
- Romania - At Herja (Kisbanya), Baia Mare (Nagybanya) district
- USA - From Rossie and Balmat, St. Lawrence Co. New York; at Hancock, Houghton Co. and in the Phoenix mine, Keeweenaw Co. Michigan; in Missouri, from many mines in Reynolds Co. and at Joplin, Jasper Co.; Galena, Cherokee Co. Kansas; and Picher, Ottawa Co. Oklahoma, in the Tri-State district; from the Elmwood mine, near Carthage, Smith Co. Tennessee; at Bisbee, Cochise Co. Arizona. In Mexico, from Santa Eulalia, and in Areponapuchic Canyon, Chihuahua; at many mines at Guanajuato; from Charcas, San Luis Potosi
- Russia - At Dalnegorsk, Primorskiy Krai.
Occurrence of Calcite and Useful Mineral Association
Calcite occurs in major rock-forming minerals; in limestones, marbles, and chalks; a common cement in clastic sedimentary rocks; as gangue in hydrothermal veins; in alkalic to mafic igneous rocks; and commonly as speleothems in caves.
It is often associated with minerals such as dolomite, celestine, fluorite, barite, pyrite, marcasite, sphalerite, zeolites, talc, chalcedony, 'chlorite', tremolite, grossular, quartz, nepheline, diopside, orthoclase, and apatite.
References