[ 39 ]
XVI. There is alſo found in the ſame Place a tranſparent Stone, ſomething like the Chian: and in others, there are many other Kinds.
XVII. Theſe are the Differences which have been mentioned as common to many Stones. But thoſe which ariſe
tion from the Onyx or Alabaſter Gem, as what we now call only the Onyx was then ſometimes called.
The Chernites, or Chermites, was a white Marble, uſed in the Sepultures of the ancient Greeks, &c. and about which there have been many Miſtakes among the later Authors: theſe, as the Species of Marble is now unknown among us, it would be but idle to enquire into.
The Porus was alſo a Marble much in Eſteem with the Ancients, but unknown to us. Its peculiar Property, as our Author obſerves, was its Lightneſs. It cut well, and bore a tolerable Poliſh, and the Statues, &c. made of it, were common in Greece, and called Πώρινα, as thoſe of the Parian Marble were called Πάρια. The Tophus, to which our Author compares this Marble for Lightneſs, is a rough Stone of the Pumice Kind, brittle, and eaſily crumbling into Powder. It is not much known in England, but common in Germany, where it is uſed inſtead of the Pumice, and called Topffſtein and Tugſtein. This was a Stone well known among the Greeks, and was what they called the Porus, without any Addition; whereas the other, here deſcribed among the Marbles by the Author, was called the Porian Marble; from its Reſemblance to this Porus. The dark tranſparent Stone, next mentioned, was probably of the Obſidianus Kind; as well as the Chian. The Antients had two or three of theſe dark Marbles, of fine Texture, in great Uſe among them. They bore a good Poliſh, were tranſparent in ſome Degree when cut into thin Plates, and reflected the Images of Things as our Looking-glaſſes do: the fineſt Kind was, for this Reaſon, called ὀψιανὸς ἀπὸ τῆς ὄψεος, which was afterwards written by the Latins, Opſianus, Opſidianus, and Obſidianus. And the true Origin of the Name being forgotten from the falſe ſpelling the Word, After-ages thought it had received it from one Obſidius, whom they imagined the firſt Finder of it.
