Porcelanite, sometimes called porcelain jasper, is a rock formed by the thermal alteration of clay and clay-like rocks. In nature, it is formed in places where clay comes into contact with hot magma, or by the burning of earth fires (e.g. coal seams). It is essentially a natural ceramic in which silica predominates. It also contains oxides of aluminium, calcium, iron and magnesium. Its colour is red, brownish red, brown, bluish grey, orange and yellow. It has a matt glassy lustre, almost waxy, and a hardness of 6,5-7,0. The offered porcelainite comes from the locality of Bučník, Komňa, Uherské Hradiště. This piece is suitable for any jewellery. The size of the stone is 11,8 x 12,0 mm.
Čeština 
