The BCCF - for information about calcium carbonate

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Calcium Carbonate

The World's Most Versatile Mineral

Calcium Carbonate Glossary

Chalk

Chalk is a poorly compacted sedimentary rock predominately composed of compacted coccoliths (a lime-secreting algae).

Dolomite

Formed as limestone (see below) but the sedimentation process occurs in the presence of magnesium resulting in a dolomitisation process.

Limestone

Limestone is also a sedimentary rock, but it is more compacted than chalk. It is formed from the remains of microscopic animals or foraminifera.

Marble

Marble is a coarse-crystalline, metamorphic rock, which is formed when chalk or limestone are recrystallised under conditions of high temperature and pressure.

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Marble geology

Recrystallised limestones

Marble is a coarse-crystalline, metamorphic rock, which is formed when chalk or limestone are recrystallised under conditions of high temperature and pressure, often a result of regional metamorphism – movement of the earth's crust .


Formation of marble deposits through intense heat and pressure

Intense folding and recystalisation due to heat and pressure acting on limestones. Accordingly, most recent marbles are found in mountainous regions. (Source: Imerys Performance Minerals)


The temperatures and pressures necessary to form marble usually destroy any fossils and sedimentary textures present in the original rock. In some cases this process has produced white marbles of exceptional brightness such as the famous deposits in Carrara in Italy.

True marble has a low porosity and may contain calcite crystals up to several centimetres in length. Large deposits of marble are to be found in North America and in Europe in Austria, Scandanvia and Italy. However the UK has no white or other marble deposits of significance though stone is imported and processed in the UK to produce high whiteness fillers and pigments.

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