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EMERALD

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Originally appearing in Volume V09, Page 332 of the 1911 Encyclopedia Britannica.
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EMERALD , a See also:

bright See also:green variety 9f See also:beryl, much valued as a See also:gem-See also:stone. The word comes indirectly from the Gr. o-µapaybos (Arabic zumurrud), but this seems to have been a name vaguely given to a number of stones having little in See also:common except a green See also:colour. See also:Pliny's " smaragdus " undoubtedly included several distinct See also:species. Much confusion has arisen with respect to the " emerald " of the Scriptures. The See also:Hebrew word nophek, rendered emerald in the Authorized Version, probably meant the See also:carbuncle: it is indeed translated avOpaE in the See also:Septuagint, and a marginal See also:reading in the Revised Version gives carbuncle. On the other See also:hand, the word baregath, rendered vtcapaylor in the LXX., appears in the A.V. as carbuncle, with the alternative reading of emerald in the R.V. It may have referred to the true emerald, but See also:Flinders See also:Petrie suggests that it meant See also:rock-crystal. The properties of emerald are mostly the same as those described under BERYL. The crystals often show simply the hexagonal See also:prism and basal See also:plane. The prisms cleave, though imperfectly, at right angles to the geometrical See also:axis; and hexagonal slices were formerly worn in the See also:East. Compared with most gems, the emerald is rather soft, its hardness (7.5) being but slightly above that of See also:quartz. The specific gravity is See also:low, varying slightly in stones from different localities, but being for the Muzo emerald about 2.67.

The refractive and dispersive See also:

powers are not high, so that the cut stones display little brilliancy or " See also:fire." The emerald is dichroic, giving in the dichroscope a bluish-green and a yellowish-green See also:image. The magnificent colour which gives extraordinary value to this gem, is probably due to See also:chromium, F. See also:Wohler found o•186% of Cr2O3 in the emerald of Muzo,—a proportion which, though small, is sufficient to impart an emerald-green colour to See also:glass. The stone loses colour when strongly heated, and M. Lewy suggested that the colour was due to an organic pigment. Greville See also:Williams showed that emeralds lost about 9% of their See also:weight on See also:fusion, the specific ,gravity being reduced to about 2.4. The ancients appear to have obtained the emerald from Upper See also:Egypt, where it is said to have been worked as See also:early as 165o B.C. It is known that See also:Greek miners were at See also:work in the See also:time of See also:Alexander the See also:Great, and in later times the mines yielded their gems to See also:Cleopatra. Remains of extensive workings were discovered in the See also:northern Etbai by the See also:French traveller, F. Cailliaud, in 1817, and the mines were re-opened for a See also:short time under Mehemet See also:Ali. " Cleopatra's Mines " are situated in See also:Jebel Sikait and Jebel Zabara near the Red See also:Sea See also:coast east of See also:Assuan. They were visited in 1891 by E.

A. See also:

Floyer, and the Sikait workings were explored in rgoo by D. A. MacAlister and others. The See also:Egyptian emeralds occur in See also:mica-schist and See also:talc-schist. On the See also:Spanish See also:conquest of See also:South See also:America vast quantities of emeralds were taken from the Peruvians, but the exact locality which yielded the stones was never discovered. The only South See also:American emeralds now known occur near See also:Bogota, the See also:capital of See also:Colombia. The most famous mine is at Muzo, but workings are known also at Coscuez and Somondoco. The emerald occurs in nests of See also:calcite in a See also:black bituminous See also:limestone containing See also:ammonites of See also:Lower Cretaceous See also:age. The See also:mineral is associated with quartz, See also:dolomite, See also:pyrites, and the rare mineral called " See also:parisite "—a fluo-carbonate of the See also:cerium metals, occurring in brownish-yellow hexagonal crystals, and named after J. J. See also:Paris, who worked the emeralds.

It has been suggested that the Colombian emerald is not in its See also:

original See also:matrix. The See also:fine stones are called canutillos and the inferior ones morallicn. In 183o emeralds were accidentally discovered in the Ural Mountains. At the See also:present time they are worked on the See also:river Takovaya, about 6o m. N.E. of See also:Ekaterinburg, where they occur in mica-schist, associated with See also:aquamarine, See also:alexandrite, See also:phenacite, &c. Emerald is found also in mica-schist in the Habachthal, in the See also:Salzburg See also:Alps, and in See also:granite at Eidsvold in See also:Norway. Emerald has been worked in a vein of See also:pegmatite, piercing slaty rocks, near Emmaville, in New South See also:Wales. The crystals occurred in association with See also:topaz, fluorspar and cassiterite; but they were mostly of rather See also:pale colour. In the See also:United States, emerald has occasionally been found, and fine crystals have been obtained from the workings for See also:hiddenite at Stony-point, Alexander See also:county, N.C. Many virtues were formerly ascribed to the emerald. When worn, it was held to be a preservative against See also:epilepsy, it cured See also:dysentery, it assisted See also:women in childbirth, it drove away evil See also:spirits, and preserved the chastity of the wearer. Administered internally it was reputed to have great medicinal value.

In consequence of its refreshing green colour it was naturally said to be See also:

good for the eyesight. The stone known as " See also:Oriental emerald " is a green See also:corundum. Lithia emerald is the mineral called hiddenite; Uralian emerald is a name given to See also:demantoid; Brazilian emerald is merely green See also:tourmaline; evening emerald is the See also:peridot; pyro-emerald is fluorspar which phosphoresces with a green glow when heated; and " See also:mother of emerald " is generally a green quartz or perhaps in some cases a green See also:felspar. See AQUAMARINE, BERYL. (F. W.

End of Article: EMERALD

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