Dolomite (mineral)

Dolomite
Dolomite (white) on talc
General
CategoryCarbonate minerals
Formula
(repeating unit)		CaMg(CO3)2
IMA symbolDol[1]
Strunz classification5.AB.10
Crystal systemTrigonal
Crystal classRhombohedral (3)
H–M symbol: (3)
Space groupR3
Unit cella = 4.8012(1),
c = 16.002 [Å]; Z = 3
Identification
ColorWhite, grey to pink, reddish-white, brownish-white; colourless in transmitted light
Crystal habitTabular crystals, often with curved faces, also columnar, stalactitic, granular, massive.
TwinningCommon as simple contact twins
Cleavage3 directions of cleavage not at right angles
FractureConchoidal
TenacityBrittle
Mohs scale hardness3.5–4.0
LusterVitreous to pearly
StreakWhite
Specific gravity2.84–2.86
Optical propertiesUniaxial (−)
Refractive indexnω = 1.679–1.681
nε = 1.500
Birefringenceδ = 0.179–0.181
SolubilityPoorly soluble in dilute HCl
Other characteristicsMay fluoresce white to pink under UV; triboluminescent.
Ksp values vary between 10−19 and 10−17
References[2][3][4][5][6]
Dolomite and calcite look similar under a microscope, but thin sections can be etched and stained in order to identify the minerals. Photomicrograph of a thin section in cross and plane polarised light: the brighter mineral grains in the picture are dolomite, and the darker grains are calcite.

Dolomite (/ˈdɒl.əˌmaɪt, ˈdoʊ.lə-/) is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO3)2. The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite (see Dolomite (rock)). An alternative name sometimes used for the dolomitic rock type is dolostone.

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Deer, W. A., R. A. Howie and J. Zussman (1966) An Introduction to the Rock Forming Minerals, Longman, pp. 489–493. ISBN 0-582-44210-9.
  3. ^ Dolomite Archived 2008-04-09 at the Wayback Machine. Handbook of Mineralogy. (PDF) . Retrieved on 2011-10-10.
  4. ^ "Dolomite". webmineral. Archived from the original on 2005-08-27. Retrieved 12 March 2024.
  5. ^ "Dolomite". mindat.org. Archived from the original on 2015-11-18. Retrieved 12 March 2024.. Mindat.org. Retrieved on 2011-10-10.
  6. ^ Krauskopf, Konrad Bates; Bird, Dennis K. (1995). Introduction to geochemistry (3rd ed.). New York: McGraw-Hill. ISBN 9780070358201. Archived from the original on 2017-02-26.