What is calcium carbonate?

Calcium carbonate is a simple compound with the chemical formula CaCO3. 
In nature this occurs as a mineral found in three distinct crystalline forms.
Although these are identical in chemical terms they differ in many other respects. 

Chalk
is a fine, microcrystalline sedimentary rock which has been produced by the sedimentation of
the shells of small fossilised creatures such as coccoliths and foraminifers. We obtain chalk at
numerous sites along the European chalk belt - from the United Kingdom through France all the way to
the island of Rügen in north Germany. 

Limestone
is also a biogenic rock, but it is more compacted than chalk. The rock was in fact formed by snails and shells. 
The size of the crystals is between that of chalk and marble. We quarry limestone from the large deposits in Orgon
(France) and Burgberg (Germany). 

Marble
is a coarse-crystalline, metamorphic rock, which is formed when chalk or limestone are recrystallised under 
conditions of high temperature and pressure. Large deposits of marble are to be found in North America and
in Europe e.g. in Austria, Norway and Carrara in Italy, the home of the pure white "statuario" from which
Michelangelo created his sculptures. 

Although more than 4 per cent of the earth's crust consists of calcium carbonate rocks,
only a few deposits are suitable for obtaining fillers. Purity, whiteness, thickness and homogeneity
are only a few of the parameters covered by our team of geologists as they prospect for
calcium carbonate deposits throughout the world.