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its Softneſs; but when it is afterwards burnt and wetted with Oil, it becomes black and ſolid. Veſſels of different Kinds, for the Service of the Table, are made of this.
LXXV. All Subſtances of this Kind are to be worked on by Iron Inſtruments; but others there are, which, as before obſerved, will not be touched by them, but muſt be cut by other Stones; and others yet, which may be cut with Iron, but the Inſtruments muſt be dull and blunt[1]: Which is much as if they were not cut by Iron.
- ↑ The Marbles, Alabaſters, and moſt other Stone of Strata, are of the Number of thoſe which we cut with blunt Iron, Inſtruments. But if we conſider our Manner of performingthis, which probably is the ſame that was uſed in this Author’s Time, and is not, without the Aſſiſtance of Water and Sand, we ſhall find, that theſe are not properly to be divided from the Claſs. of thoſe uſually cut with other Stones; for, in reality, the Sand in this Caſe does more than the Iron, and is a ſimilar Subſtance to the Powder of hard Stones uſed to Gems; tho' coarſer; The Art of cutting and poliſhing the harder Gems with other Stones was known very early in the World: We have Accounts from ſome of the earlieſt Authors, of Fragments of Diamonds being ſet in a convenient Manner for handling, and made into Tools for the working on other Gems. Dia-
mus. I have, among the Ollares, one of the coarſe grey and black Kind; the Pierre Ollaire a gros Graines of Bomare; which becomes of a perfect black after it has been two or three Times in the Fire. Perhaps this is the very Stone which Pliny ſpeaks of here. I had mine from Minorca.
