ZIRCON AND HYACINTH. 23 Uses. As common zircon is considered by jewellers one of the gems, it is frequently cut and polished, and used for ornamental purposes. The greyish-white and yellowish- white varieties are the most highly valued, on account of their resemblance to the diamond. The darker coloured varieties can be deprived of their colour by exposure to heat: hence artists generally employ this method, when they intend to employ zircon in place of diamond. ^ Like the diamond, it is cut into the table, rose and brilliant forms, and is used for jewelling watches, ear-pendents, necklaces, and, on account of the intermixture of gpey in the colour, it is particularly valued in some countries as an ornament in mourning-dress. When cut, it exhibits in a faint degree the play of colours of the diamond ; and hence it is not unfrequently sold as an inferior kind of diamond. The Hyacinth is also esteemed by jewellers, and, when pure, and of considerable size, is employed in various kinds of ornamental work. But it seldom occurs large, and in trade, other minerals, as cinnamon-stone, pale garnets, and rock-crystals, are frequently substituted for it. III. RUBY FAMILY. This Family contains the following species: Auto- malite, Ceylanite, Spinel, Sapphire, Emery, Corundum, and Chrysoberyl. 1. Automalite.