7Some are found in certain places in a native state, and thence dug up, whilst others are composed of different substances, ground and mixed together, so as to answer the same purpose. First we shall explain the nature of that which is found native, called by the Greeks ὦχρα. This, as in Italy, is discovered in many places, but the best is the Attic sort, which cannot now be procured, for in working the silver mines at Athens, if by chance they fell upon a vein of ochre, they followed it up just as they would one of silver. Hence the ancients used abundance of ochre in their finishings.
7As for colours, some are natural products found in fixed places, and dug up there, while others are artificial compounds of different substances treated and mixed in proper proportions so as to be equally serviceable. We shall first set forth the natural colours that are dug up as such, like yellow ochre, which is termed ωχρα in Greek. This is found in many places, including Italy, but Attic, which was the best, is not now to be had because in the times when there were slaves in the Athenian silver mines, they would dig galleries underground in order to find the silver. Whenever a vein of ochre was found there, they would follow it up like silver, and so the ancients had a fine supply of it to use in the polished finishings of their stucco work.