MODE V. PORPHYRY. 81 



golden (Jrops ; that is, as Wad explains, a dark 

 ollite interspersed with golden mica *. The white 

 was probably a spotted marble or alabaster, for 

 the ancients arranged stones by faint resemblances ; 

 but white ollite, or rather massive steatite, is not 

 unknown in Saxony and other countries. 



Green porphyry occurs in large blocks near 

 Ostia, which, as Ferber observes, was the old har- 

 bour where the Egyptian ships unloaded |: but 

 all the other ships bound for Rome also arrived 

 there; nor do I find any mention of green por- 

 phyry in the memoir concerning Egyptian geo- 

 logy, which M. Roziere presented to me. This 

 porphyry contains crystals of siderite, and fre- 

 quently spots of chalcedony. Ferber observed Ferbert 



observations. 



the following varieties : 



Dark green, with fair green spots ; common. 

 Dark green, with white spots. 

 Dark green, with black spots. 



* Fossil. JEgypt. p. 57. This subject will be further illustrated 

 in treating of the Magnesian Rocks, and of the ancient marbles, 

 where it will be seen that the green porphyry was unknown till the 

 latter times of the Roman empire. In describing this substance, 

 Da Costa, p. 288, justly observes, that there are no Grecian nor 

 Roman relics of it ; and he concludes that very little was found even 

 in Egypt. It is now well known that it is not an Egyptian pro- 

 duct ; but vast masses remain near the port of Ostia, where it was 

 probably left on the irruptions of the barbarians in the fifth century, 

 when the arts were interrupted and abandoned. 



f Travels in Italy, 225. 

 VOL. I. G 



