2$6 Count de Bournon's Description of 
degree of hardness to others ; and, as those which were the hard- 
est most commonly came from the East Indies, all hard gems were 
called oriental, as a general mark of discrimination. The chief 
distinguishing character of gems was then derived from their 
colour, which had caused them to be denominated sapphire, 
ruby, amethyst, topaz, emerald, chrysolite, &c. and it was 
thought sufficient to add to these names the epithet oriental, to 
distinguish those among them whose hardness was superior to 
that of the others. 
Rome' de Lisle was the first mineralogist who threw a 
gleam of light, into the obscurity which existed in this confused 
assemblage of stones. His classification of gems, although it had 
not yet attained the degree of perfection to which the science of 
crystallography (of which he had just laid the foundation) 
may hereafter carry it, was undoubtedly one of the greatest 
steps mineralogy had made, at the time when the second edition 
of his work, upon this new character of stones, was published. 
After having fixed, according to their different characters, and 
particularly according to that which was derived from their 
crystalline forms, the place which each of the species com- 
posing this particular class of lithology ought to occupy, he 
placed at the head of them, under the title of oriental ruby , 
all those stones which, being possessed of a degree of hard- 
ness superior to that of all others, (except the diamond,) ad- 
mitted a more brilliant polish, and appeared under the form 
of a hexaedral pyramid, or of two, joined base to base, the solid 
angle of whose summit, taken upon two of the opposite faces, 
varied, according to him, from 20° to 30°. He added also, that 
this stone presented all sorts of colours, either separately, or 
united together in the same stone. Nearly at the same time, 
