Marble,granite,onyx from Italy.Complete Project for residencial and commercial , hotel,villa,onice,marmo,marbre,marmol, travertine,granite,stone.
Although it is still (2007) regarded as a valid mineral species for historical reasons, Opal is not a true mineral in the accepted sense of the word as it is either ...
Whelan, J.A. and S.S. Goldich (1961): New data for hisingerite and neotocite. Amer. Mineral., 46, 1412-1423. Clark, A.M., A.J. Easton, and M. Mount (1978): A study of ...