Limestone or calcium carbonate is a cream, grey or yellow, predominantly organogenic sedimentary rock.
The rock mainly consists of calcite and aragonite. In its natural form, it exhibits low resistance to wear and tear; however, after several freeze-thaw cycles, this property improves spectacularly as limestone has self-cementing properties.
Bulk density: 2.3 - 2.6 t/m3
Water absorption capacity: 2.0 - 5.0 %
Compressive strength: 0.17 g/cm2
Compressive strength: 33.5 N/mm2
MOHS hardness: 4
Freeze-thaw resistance: depending on origin
Limestone may be found as:
-polychromic limestone, recommended only for indoor vertical and horizontal tiling, sculptural elements, stairs and counter-steps.
-calcareous sandstone, recommended for indoor and outdoor tiling: especially vertical tiling, ventilated facades, fireplaces, decorative and sculptural objects, massive architectural elements (frames, columns and balusters).
Limestone has been the most popular rock since the building of the pyramids until today, while the relatively easy mining of this rock has led to at least one limestone quarry operating in every region of the world.
In Romania, limestone is extracted in Podeni, Cluj County. The most widely sold varieties of limestone are Vratza, White Timber, Grey Timber, Creme Fosil, Caliza Capri, Caliza Marbela.