Of all the gem-stones zircon alone approaches diamond in brilliance of lustre, and it also possesses considerable ‘fire’; it can, of course, be readily distinguished by its inferior hardness, but a judgment based merely on inspection by eye might easily be erroneous. According to Church, who has made a lifelong study of zircon, the green and yellowish stones of the first variety emit a brilliant orange light when being ground on a copper wheel charged with diamond dust, and the golden stones of the intermediate type glow with a fine orange incandescence in the flame of a bunsen burner; the latter phenomenon is supposed to be due to the presence of thoria. The leaf-green stones almost invariably show a series of parallel bands in the interior. Zircons vary from 5s. to 15s. a carat, but exceptional stones may be worth more. By far the finest stones come from Ceylon. The colourless stones are there known as ‘Matura diamonds,’ and the hyacinth includes garnet (hessonite) of similar colour, which is found with it in the same gravels. The stones are always water-worn. Small hyacinths and deep-red stones come from Expailly, Auvergne, France, and yellowish-red crystals are found in the Ilmen Mountains, Orenburg, Russia. Remarkably fine red stones have been discovered at Mudgee, New South Wales, and yellowish-brown stones accompany diamond at the Kimberley mines, South Africa. CHAPTER XXVII CHRYSOBERYL (_Chrysolite_, _Cat’s-Eye_, _Cymophane_, _Alexandrite_) Chrysoberyl has at times enjoyed fleeting popularity on account of the excellent cat’s-eyes cut from the fibrous stones, and in the form of alexandrite it meets with a steadier, if still limited, demand. It is a gem-stone that is seldom met with in ordinary jewellery, although its considerable hardness befits it for all such purposes.