The turquoise has in all likelihood been used as a gem from a very remote antiquity, since the range of mountains where it is plentifully found is situated at no great distance from the southern shore of the Caspian Sea, near to, if not within, the area believed by many to have been the cradle of the human race. By some scholars, it is thought highly probable that the turquoise was used for inlaying the delicate and beautiful gold-work of ancient Greece; and at all events, there is a cameo portrait of a classic Greek prince in this mineral among the specimens in the famous collection of Marlborough gems. There is some doubt about the name this precious stone was known by in Pliny’s time. He mentions that the _callais_, which was probably the turquoise, was found in Asia, where it occurred projecting from the surface of inaccessible rocks, whence it was obtained by means of slings; but these were the days of fables. That it was known to the ancient Romans is, however, proved by the fact that there still exist some, though only a very few, of their works of art cut in this mineral. Want of certainty about the name applied to the turquoise in classic times leaves us in doubt as to what mystic virtues were then attributed to it. But in the middle ages, the turquoise, like other gems, was believed to have wonderful properties; indeed, it was credited with more supernatural virtues than most of them. The wearer of it had both his sight strengthened and his spirits cheered; he enjoyed immunity from the consequences of a fall by the gem itself breaking, in order to save his bones; and his turquoise, like himself, turned pale if he became sick. When its possessor died, it entirely lost its colour; but recovered it again on passing into the hands of a new owner. In some mysterious way, when suspended by a string, it correctly struck the hours on the inside of a glass vessel. Other precious stones have lost all the marvellous powers that belonged to them for centuries: the emerald no longer relieves the fatigued eyesight; the diamond cannot now dispel fear; the sapphire, though still cold to the touch, has ceased to be able to extinguish fire. In these perverse days, the hailstorm comes down even upon the wearer of an amethyst, and bright red coral attracts rather than repels robbers. But the turquoise still retains one of its mysterious properties, and flaunts it in the face of modern science. Sometimes slowly, sometimes suddenly, it unaccountably turns pale, becomes spotted, or changes from blue to white; and specimens that behave in this capricious manner are found more commonly than those whose colour is distinctly permanent.