New species of precious stones are repeatedly brought into existence, and fresh ones are found all at once, destitute of names. Thus, for example, there was a stone formerly discovered in the gold-mines of Lampsacus, which, on account of its extraordinary beauty, was sent to King Alexander, as we learn from Theophrastus.[1] Cochlides,[2] too, which are now so common, are rather artificial productions than natural, and in Arabia there have been found vast masses of them; which are boiled, it is said, in honey, for seven days and nights without intermission. By doing this, all earthy and faulty particles are removed; after which, the mass, thus cleansed and purified, is adorned by the ingenuity of artists with variegated veins and spots, and cut into such shapes as may be most to the taste of purchasers. Indeed, these articles, in former times, were made of so large a size, that they were employed in the East as frontals for the horses of kings, and as pendants for their trappings.[3]

All precious stones in general are improved in brilliancy by being boiled in honey, Corsican honey more particularly; but acrid substances are in every respect injurious to them. As to the stones which are variegated, and to which new colours are imparted by the inventive ingenuity of man, as they have no name in common use, they are usually known by that of "physis;"[4] a name which claims for them, as it were, that admiration which we are more ready to bestow upon the works of Nature. But really, these artificial stones have names without end, and I could never think of recounting the infinite series of them, coined as they have been by the frivolous tendencies of the Greeks.

Having already described the more noble gems, and indeed those of inferior quality which are found among the stones that are held in high esteem, I must content myself with knowing that I have pointed out those kinds which are the most deserving of mention. It will be as well, however, for the reader to bear in mind, that, according to the varying number of the spots and inequalities on their surface, according to the numerous intersections of lines and their multiplied tints and shades, the names of precious stones are subject to repeated changes; the material itself, for the most part, remaining just the same.