A chemical compound, with chemical formula CaCO3. Calcium carbonate is widely used as an extender in paints, in particular matte emulsion paint where typically 30% by weight of the paint is either chalk or marble. Calcium carbonate is known as whiting in ceramics/glazing applications, where it is used as a common ingredient for many glazes in its white powdered form. When a glaze containing this material is fired in a kiln, the whiting acts as a flux material in the glaze. It is also known as gilders chalk. In North America, calcium carbonate has begun to replace kaolin in the production of paper. Europe has been practicing this as alkaline papermaking or acid-free papermaking for some decades. Precipitated calcium carbonate (PCC), has a very fine and controlled particle size, on the order of 2 micron in diameter, useful in coatings for paper.
We stock Calcium Carbonate in two grades, based on conservators needs of polishing silver. The standard is used most general applications. The Ultra Fine is a product with 1.6 micron scalenohedral particle size, which makes it ideal for the practice of polishing silver with as minimal scratching as possible.