Next after the kinds above described, the smaragdus of Æthiopia is held in high esteem; being found, as Juba tells us, at a distance of twenty-five days’ journey from Coptos. These are of a bright green, but are seldom to be met with perfectly clear or of an uniform colour. Democritus includes in this class the stones that are known as “herminei,” and as “Persian” stones; the former of which are of a convex, massive shape, while the latter are destitute of transparency, but have an agreeable, uniform colour, and satisfy the vision without allowing it to penetrate them; strongly resembling, in this respect, the eyes of cats and of panthers, which are radiant without being diaphanous. In the sun, he says, they lose their brilliancy, but they are radiant in the shade, the brightness of them being seen at a greater distance than in the case of other stones. One other fault, too, in all these stones is, that they often have a colour like that of honey or rancid oil, or else are clear and transparent, but not green. These defects exist in the smaragdi of Attica,[3021] more particularly, which are found in the silver-mines there, at a place known by the name of Thoricos.[3022] These last are never so massive as the others, and are always more pleasing to the sight when viewed from a distance: lead ore, too, is often to be detected in them, or, in other words, they have a leaden appearance when looked at in the sun.[3023] One peculiarity in them is, that some of them become impaired by age, gradually lose their green colour, and are even deteriorated by exposure to the sun. Next to the stones of Attica come those of Media, a variety which presents the most numerous tints of all, and sometimes approaches sapphiros[3024] in colour. These stones are wavy,[3025] and represent various natural objects, such as poppy-heads, for example, birds, the young of animals, and feathers: all of them appear naturally of a green colour, but become improved by the application of oil. No stones of this species are of a larger size than these.