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[[File:1280px-Dolomite-Magnésite- Navarre.jpg|thumb|400px|Dolomite et magnésite - Carrière Azcárate, Eugui, Esteribar, Navarre, Espagne. Photo by [https://commons.wikimedia.org/wiki/User:Archaeodontosaurus Didier Descouens].]]
{{publication
| image = CN24Cover.jpg
| width = 120px
| series = Course Notes
| title = Dolomitization
| part =
| chapter =
| frompg = 1
| topg = 20
| author = Lyndon S. Land
| link = http://archives.datapages.com/data/alt-browse/aapg-special-volumes/cn24.htm
| pdf =
| store =
| isbn = 0-89181-173-7
}}
[[File:1280px-Dolomite-Magnésite- Navarre.jpg|thumb|300px|Dolomite et magnésite - Carrière Azcárate, Eugui, Esteribar, Navarre, Espagne. Photo by [https://commons.wikimedia.org/wiki/User:Archaeodontosaurus Didier Descouens].]]
==Mineralogy==
==Mineralogy==
Dolomite is a rhombohedral carbonate with the ideal formula CaMg(CO<sub>3</sub>)<sub>2</sub> in which calcium and magnesium occupy preferred sites. In the ideal mineral, planes of CO<sub>3</sub> anions alternate with planes of cations with the c-axis of the crystal perpendicular to the alternating stacked anion and cation planes. Ordering occurs by the additional alternation of cation planes containing only calcium with cation planes containing only magnesium ([[:file:CN24FG1.jpg|Figure 1]]). It is possible to conceive of a mineral having the same composition as ideal dolomite ((Ca<sub>0.5</sub>Mg<sub>0.5</sub>)(CO<sub>3</sub>) in which all cation planes are alike, containing equal numbers of calcium and magnesium ions. Such a mineral is not dolomite. Such a disordered arrangement of ions occupies more volume than that of the ideal dolomite structure and is unstable with respect to an ordered phase.
Dolomite is a rhombohedral carbonate with the ideal formula CaMg(CO<sub>3</sub>)<sub>2</sub> in which calcium and magnesium occupy preferred sites. In the ideal mineral, planes of CO<sub>3</sub> anions alternate with planes of cations with the c-axis of the crystal perpendicular to the alternating stacked anion and cation planes. Ordering occurs by the additional alternation of cation planes containing only calcium with cation planes containing only magnesium ([[:file:CN24FG1.jpg|Figure 1]]). It is possible to conceive of a mineral having the same composition as ideal dolomite ((Ca<sub>0.5</sub>Mg<sub>0.5</sub>)(CO<sub>3</sub>) in which all cation planes are alike, containing equal numbers of calcium and magnesium ions. Such a mineral is not dolomite. Such a disordered arrangement of ions occupies more volume than that of the ideal dolomite structure and is unstable with respect to an ordered phase.