AGATE. 
423 
way was Pyrgoteles, who flourished in the reign of 
Alexander, and had the exclusive privilege of en- 
graving the conqueror ; as Lycippus was the only 
sculptor who was permitted to make statues of him. 
Under the reign of Augustus, the Roman empire 
prod uced several very celebrated engravers of cameos ; 
so that from the joint productions of these men a con- 
siderable number of engraved gems have been handed 
down to us, and now contribute to enrich our cabi- 
nets, It appears that the antient artists collected 
their stones for this purpose from Egypt, and that 
at present they chiefly come from Asia Minor, and 
Arabia, 
There are two kinds of onyx: one is of a pale flesh 
colour with white lines, or nail-coloured onyx ; and 
the other composed of black and white veins, called 
the oriental onyx. 
