tourmaline is remarkable, although of little value as a test in the case of a cut stone, is of great scientific interest, because it is strong evidence of the peculiar crystalline symmetry pertaining to its molecular arrangement. Tourmalines range in price from 5s. to 20s. a carat according to their colour and quality, but exceptional stones may command a higher rate. Tourmaline is usually found in the pegmatite dykes of granites, but it also occurs in schists and in crystalline limestones. Rubellite is generally associated with the lithia mica, lepidolite; the groups of delicate pink rubellite bespangling a background of greyish white lepidolite are among the most beautiful of museum specimens. Magnificent crystals of pink, blue, and green tourmaline have been found in the neighbourhood of Ekaterinburg, principally at Mursinka, in the Urals, Russia, and fine rubellite has come from the Urulga River, and other spots near Nertschinsk, Transbaikal, Asiatic Russia. Elba produces pink, yellowish, and green stones, frequently particoloured; sometimes the crystals are blackened at the top, and are then known locally as ‘nigger-heads.’ Ceylon supplies small yellow stones—the original tourmaline—which are confused with the zircon of a similar colour, and rubellite accompanies the ruby at Ava, Burma. Beautiful crystals, green and red, often diversely coloured, come from various parts, such as Minas Novas and Arassuahy, of the State of Minas Geraes, Brazil. Suitable gem material has been found in numerous parts of the United States. Paris and Hebron in Maine have produced gorgeous pink and green crystals, and Auburn in the same state has supplied deep-blue, green, and lilac stones. Fine crystals, mostly green, but also pink and particoloured, occur in an albite quarry near the Conn River at Haddam Neck, Connecticut. All former localities have, however, been surpassed by the extraordinary abundance of superb green, and especially pink, crystals at Pala and Mesa Grande in San Diego County, California. As elsewhere, many-hued stones are common. The latter locality supplies the more perfectly transparent crystals. Kunz states that two remarkable rubellite crystals were found there, one being 45 mm. in length and 42 mm. in diameter, and the other 56 mm. in length and 24 mm. in diameter. Madagascar, which has proved of recent years to be rich in gem-stones, supplies green, yellow, and red stones, both uniformly tinted and particoloured, which in beauty, though perhaps not in size, bear comparison with any found elsewhere. CHAPTER XXV PERIDOT