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192 NATURAL HISTORY OF GEMS.
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Although the
use of this mineral is coeval with the first invention of
gem-engraving, which indeed in its proper sense cannot be effected
without its aid, yet the earliest extant mention of it by a specific
name is that made by Dioscorides (a contemporary of the Triumvirs), who
has (v. 165), " The Smyris is a stone with which gem-engravers polish
the gems." Theophrastus (44) mentions the same use of the mineral, but
appears not to have had any distinctive denomination for it, his words
merely being, "And again, the stone wherewith they engrave signets is
the same as that of which whetstones are made, or else similar to it,
and the best kind is brought from Armenia."
The
very chapter in which Theophrastus had given some details of the
process is unfortunately one of the most corrupt and mutilated in the
whole treatise ; but it may be gathered from what remains that he
expresses his surprise at the fact that the substance in question can
be cut up and shaped by a steel tool, and yet can bite upon gems that
the steel will not touch.
¢êüíáé with the Greeks, as Cotes with the Latins, were terms used indifferently to denote the agent with which steel tools were sharpened and " hard stones "* engraved, inasmuch as a piece of compact Emery was employed in both
*
' Hard stones ' is the technical term in the lapidary's art for all the
species which resist cutting by a steel tool, however hard its temper.
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