What does dolomite mean?
Dolomite is a carbonate mineral with the chemical formula CaMg(CO₃)₂, made up of calcium magnesium carbonate, and it is also the name given to the sedimentary rock that consists mainly of this mineral — though geologists sometimes prefer the term dolostone for the rock to keep the two senses distinct. Typically white, cream, grey, or pale pink, the mineral crystallises in rhombohedral form and is closely related to calcite, differing by its significant magnesium content. Dolomite rock forms extensive geological formations worldwide, most famously the Dolomite Mountains of northern Italy, from which the mineral takes its name. In practical use, dolomite is quarried for construction aggregate, crushed for use in agriculture to neutralise acidic soil and supply magnesium, and processed as a source of magnesium compounds. It also appears in ornamental stonework and in the manufacture of refractory materials for furnaces. Though a specialist term, it surfaces in gardening advice, travel writing about the Alps, and industrial contexts alike.
A carbonate mineral of calcium magnesium carbonate, CaMg(CO₃)₂, typically white, grey, or pinkish, used industrially and agriculturally.
"The kiln was charged with crushed dolomite to produce refractory lime."
This is the original and strictest sense of the word.
Sedimentary rock composed predominantly of the mineral dolomite; also called dolostone.
"Layers of dolomite exposed along the gorge record an ancient shallow sea."
Some geologists reserve 'dolostone' for the rock to distinguish it clearly from the mineral.
The plural usually refers to occurrences or varieties of the mineral/rock; capitalised 'Dolomites' refers specifically to the Alpine mountain range in northeastern Italy.
"Coarse white dolomites were visible throughout the outcrop."
The mountains of northern Italy are so rich in this mineral that an entire Alpine range — the Dolomites — is literally named after it, not the other way round.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of dolomite
The word dolomite derives from the name of Déodat de Gratet de Dolomieu, the French geologist who first described the mineral in the late eighteenth century, around 1791–1792; the mineral was named in his honour shortly afterwards. The term entered English via French 'dolomie' and German usage in early scientific literature. The Italian Dolomite mountains take their name directly from the mineral, making this one of the rare cases where a place name commemorates a scientist through his eponymous mineral.
How dolomite is actually used
Strictly, 'dolomite' names both the mineral and the rock; some geologists prefer the term 'dolostone' for the rock to avoid ambiguity. The word is technical rather than colloquial, appearing mainly in geology, mining, agriculture, and building-materials contexts.
Easily confused with dolomite
Calcite is pure calcium carbonate (CaCO₃), whereas dolomite is a calcium magnesium carbonate containing magnesium as well as calcium.
Limestone is composed chiefly of calcite, while dolomite (or dolostone) is composed chiefly of the mineral dolomite and reacts less vigorously with dilute acid.