Beryl
emerald aquamarine jewellery
BERYL, a mineral species which includes, in addition to what are ordinarily known as beryls, the aquamarine or precious beryl and the emerald. The similarity between the beryl and the emerald was pointed out by Pliny, and the only points of distinction are the green colour of tho emerald and the somewhat superior hardness of
the beryl. The colour of the emerald is generally believed to be due to the presence of a minute portion of oxide of chromium, although id. Lewy asserts, from analysis of Muzo emeralds, that it is really owing to the presence of organic matter. Their composition is - The metal glucinum, from its presence in the beryl, is sometimes termed
beryllium. The beryl crystallizes in six-sided prisms with the crystals often deeply striated in a longitudinal direction ; its hardness in the mineralogical scale is from 7.5 to 8, and its specific gravity from 2.67 to 2.732. Leaving out of account the emerald, the colours of the beryl range from blue through soft sea green to a pale honey yellow, and in some cases the stones are entirely
colourless. The aquamarine is so named on account of its bluish green colour, "qui viriditatem purl marls imitantur" (Pliny, NI II., xxxvii. 20). The chrysoberylus, chrysoprasus, and chrysolithus of ancient jewellery appear to some extent at least to have been names applied to different shades of beryl. The beryl was highly prized for use in jewellery by the Romans, by whom it was cut into
six-sided prisms (cylindri) and mounted as ear-drops. Some of the finest examples of ancient Greek and Roman gem engraving are found executed in beryl. " The grandest intaglio extant of the Roman period is upon an aquamarine of the extraordinary magnitude of 2i by 2-4. inches : the bust of Julia Titi signed by the artist EY0A.00 EIIOIEI. For • nearly a thousand years it formed the knosp of a
golden reliquiary presented by Charlemagne to the abbey of St Denys, in which it was set with the convex back uppermost, being regarded as an invaluable emerald" (King's Precious Stones, Gems, and Precious 1Ietals). The great abundance of aquamarine and other forms of beryl in modern times has very much depreciated its value for use in jewellery, but it is still set in bracelets, necklaces, Arc.,
and used for seals. The finest aquamarine known is a large stone, in size and shape somewhat like a small calf's head, weighing 18 Its the property of the emperor of Brazil. A beryl weighing 2900 lb and another of 1076 lb weight have been found at Grafton, New Hampshire, in the United States ; but these gigantic stones are opaque, and of no value for jewellery. Beryl is found widely disseminated,
occurring, among other localities, in Siberia, Canjargum in Hindustan, Rio San Matteo in Brazil, Ehrcnfriedersdorf in Saxony, and Schlackenwald in Bohemia. In the United Kingdom it occurs in the Mourne Mountains, county Down ; in the neighbourhood of Killiney, county Dublin ; in county Wicklow ; in several places in Cornwall ; and in Aberdeenshire in the granite of Rubislaw (Davidsonite); besides
occurring in the alluvium of the upper reaches of the Dee and Don. In the United States it is found in the states of New Hampshire, Maine, Massachusetts, Connecticut, and Pennsylvania. 
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