NATURAL STONE

In the case of natural stone, a distinction must be made between hard and soft rock. The hard types of rock include granite, gneiss, quartzite and porphyry. The soft types of rock include sandstone as well as lime­stone, e.g. marble (Thassos, Carrara, Estremoz, Palisandro etc.), Juras­sic marble, Solnhofer stone, travertine, Botticino and Trani.

CAST STONE

Cast stone consists of pieces of natural stone which are bound together by means of synthetic resin or cement. Examples of cement-bound cast stone are concrete ashlar or terrazzo. Examples of resin-bound cast stone are agglomerate marble or agglomerate granite.

SENSITIVITY TO ACIDS

Particular kinds of natural stone consist mainly of calcium carbonate and are called limestones. Limestone, for example marble, is sensitive to acids! Cement-bound cast stones, such as concrete ashlar, are also acid ­sensitive. We strongly advise avoiding the use of acidic cleaning agents for these types of stone.