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Uses of Dolomite
Dolomite and limestone are used in similar ways. They are crushed and used as an aggregate in construction projects. They are kiln-fired in the manufacture of cement. They are cut into blocks and slabs for use as a dimension stone. They are calcined to produce lime. In some of these uses, dolomite is preferred. Its…
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Metamorphism of Dolomite
Dolomite behaves like limestone when it is subjected to heat and pressure. It begins to recrystallize as the temperature rises. As this occurs, the size of the dolomite crystals in the rock increases, and the rock develops a distinctly crystalline appearance. If you examine the photo of granular dolomite, you will see that the rock…
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“Dolomite Rock” and “Dolostone”
Some geologists are uncomfortable using the word “dolomite” for both a mineral and a rock of the same composition. They instead prefer using “dolomite rock” or “dolostone” when speaking of the sedimentary rock and “dolomite” when speaking of the mineral. Although these terms simplify communication and improve accuracy, many geologists continue to use the word “dolomite” for both the mineral…
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Identification in the Field and Classroom
Dolomite is slightly harder than limestone. Dolomite has a Mohs hardness of 3.5 to 4, and limestone (composed of the mineral calcite) has a hardness of 3. Dolomite is slightly less soluble in dilute hydrochloric acid. Calcite will effervesce vigorously in contact with cold, dilute (5%) hydrochloric acid, while dolomite produces a very weak effervescence. These differences…
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Dolomitization
Dolomite is very common in the rock record, but the mineral dolomite is rarely observed forming in sedimentary environments. For this reason it is believed that most dolomites form when lime muds or limestones are modified by postdepositional chemical change. Dolomite originates in the same sedimentary environments as limestone – warm, shallow, marine environments where…
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What is Dolomite?
Dolomite, also known as “dolostone” and “dolomite rock,” is a sedimentary rock composed primarily of the mineral dolomite, CaMg(CO3)2. Dolomite is found in sedimentary basins worldwide. It is thought to form by the postdepositional alteration of lime mud and limestone by magnesium-rich groundwater. Dolomite and limestone are very similar rocks. They share the same color ranges of white-to-gray and white-to-light…