(4) TIFFANY The lovely orange brilliant, weighing 125⅜ carats, which is in the possession of Messrs. Tiffany & Co., the well-known jewellers of New York, was discovered in the Kimberley mine in 1878. CHAPTER XIX CORUNDUM (_Sapphire_, _Ruby_) Ranking in hardness second to diamond alone, the species known to science as corundum and widely familiar by the names of its varieties, sapphire and ruby, holds a pre-eminent position among coloured gem-stones. The barbaric splendour of ruby (Plate I, Fig. 13) and the glorious hue of sapphire (Plate I, Fig. 11) are unsurpassed, and it is remarkable that the same species should boast such different, but equally magnificent, tints. They, however, by no means exhaust the resources of this variegated species. Fine yellow stones (Plate I, Fig. 12), which compare with topaz in colour and are its superior in hardness, and brilliant colourless stones, which are unfortunately deficient in ‘fire’ and cannot therefore approach diamond, are to be met with, besides others of less attractive hues, purple, and yellowish, bluish, and other shades of green. Want of homogeneity in the coloration of corundum is a frequent phenomenon; thus, the purple stones on close examination are found to be composed of alternate blue and red layers, and stones showing patches of yellow and blue colour are common. Owing to the peculiarity of their interior arrangement certain stones display when cut _en cabochon_ a vivid six-rayed star of light (Plate I, Fig. 15). Sapphire and ruby share with diamond, pearl, and emerald the first rank in jewellery. They are popular stones, especially in rings; their comparative rarity in large sizes, apart from the question of expense, prevents their use in the bigger articles of jewellery. The front of the stones is usually brilliant-cut and the back step-cut, but Indian lapidaries often prefer to cover the stone with a large number of triangular facets, especially if the stone be flawed; star-stones are cut more or less steeply _en cabochon_.