GEMS AND PRECIOUS STONES. 29
Emerald.
This is the blight, transparent, dark green variety of the beryl. It has been highly prized from the earliest times as a gem-stone, on account of its great brilliancy and beauty. It has always maintained its position as one of the most desirable stones for ornamental purposes, and there is no doubt about its use in the most remote ages. Necklaces of emeralds have been found at Herculaneum and at other places.
The Orientals have always had a great veneration for these gems ; they believed that they had the power to impart courage to the wearer, and to protect one from the plague. The ancients supposed them to be good for the eyes, and to be a remedy for various diseases.
The natives of Peru venerated the emerald as the abode of their favourite divinity. The chief goddess of Peru was supposed to be an emerald, and the principal offerings made to it consisted of this gem. During the invasion of Mexico the (Spaniards carried off immense quantities of emeralds, many of which found their way into the lioyal Treasury of Spain. After the conquest of the New World these gerns became very plentiful, and were in great demand. The Dresden Museum contains a large uncut emerald, while the collection at Munich has several of large size ; these were from Peru. The treasury of Eussia contains many fine emeralds, and the Crown jewels of many countries are more or less ornamented with these gems.
In the London Exhibition of 1851 there was shown a very fine emerald of a beautiful colour ; it was 2 inches in length, and across the three diameters measured 2-1/4, 2-1/2, and 1-7/8 inches respectively. Its weight was S oz. 18 dwt. This emerald was obtained at Muzo, near Santa Ee de Bogota, in South America. It was taken to England by Dom Pedro, from whom it was purchased by the Duke of Devonshire.
A splendid girdle of an Indian chief was also shown at the same exhibition, made of slices from a large and beautiful emerald, advantage having been taken of the natural basal cleavage of this mineral. These slices were surrounded by diamonds, some of which were in their natural state. The slices of the emerald in this girdle were 1/4 of an inch in thickness. This was the mode of mounting this gem previous to the year 1456, so that, without doubt, this girdle was manufactured previous to that date.
There is a magnificent specimen in the Townshend collection ; it is perfect in colour, and measures 1/2 an inch across. Many other historical emeralds might be mentioned, but the above are sufficient to illustrate the great value placed upon these gems by the people of many countries for centuries past.
Mr. Streeter states that the value of the emerald ranges from 5s. a carat for very light coloured stones, up to £50 to £60 a carat for very fine dark coloured gems without flaws. These last are very rare, because the emerald is so rarely found perfect, that " an emerald without a flaw " has become a common expression. The basal cleavage, too, is often detrimental to good stones, and the precaution is taken of keeping them from the light.for some time after removal from the mine.
It is generally supposed that the name "Emerald Isle," as given to Ireland, is because of its remarkably green verdure, but the name is also in some measure connected with the emerald itself. Pope Adrian IV, when he issued his famous Pull in 1156, granting the sovereignty over the island to the King of England, is stated to have sent to Henry II a ring set with an emerald, as the instrument of his investiture with the dominion of the island.
The substances most resembling the emerald are green spinel, green glass, green garnets, and green sapphires. The former is easily distinguished by its higher specific gravity, and by its crystallizing in the cubical system (the
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