From Ohio History Central
Dolomite, Logan County, Ohio; N 4284

Dolomite was named for the French mineralogist Deodat de Dolomieu. It is common in a sedimentary rock called dolostone. Dolostone is known also as dolomite, or sometimes as dolomitic limestone. Dolomite differs from calcite, the main component of limestone, because it contains the element magnesium (Mg) as well as calcium (Ca). The chemical industry uses the mineral dolomite in making magnesium salts including magnesia, which is used in medicine. Builders use the rock dolomite as both structural and ornamental stone. The beautiful "Dolomites" in northeastern Italy (Dolomiti in Italian), form one of the principal ranges of the Alps.


Dolomite occurs worldwide, in many places, with some of the most famous in Europe and North America. Dolomite has been reported in 19 counties in Ohio.In western Ohio small crystals occur at some sites, and granular aggregates are found in cavities and cracks in dolostone. Also, crystals and granular aggregates of the mineral are found in veins of limestone concretions of the Ohio Shale.


  • Carlson, Ernest H., ed. Minerals of Ohio; Ohio Division of Geological Survey, Columbus, OH; Bulletin 69; 1991.
  • Pough, Frederick H. A Field Guide to Rocks and Minerals; Houghton Mifflin, Boston, MA; 1976.
  • Sorrell, Charles A. Rocks and Minerals; Golden Press, New York, NY; 1973.
Chemical Composition:Calcium Magnesium Carbonate (CaMg(CO3)2)
Mineral Class:Carbonates
Crystal Habit:Generally well crystallized with curved, saddle-shaped faces on the crystals; these crystals usually grouped but sometimes single; also granular or massive
Specific Gravity:2.8 - 3.0
Hardness:3 1/2 - 4
Color:White, tan, pink, gray; brown or black when iron is present.
Transparency: Transparent to translucent
Luster:/td> Vitreous
Occurence:<img width="195" height="172" src="images/naturalHistory/minerals/dolomitemap.gif" alt="" />

See Also