BISILICATES, 200 
marine includes clear beryls of a sea-grecn, or pale-bluish or 
bluish-green tint. 
Composition. SeeShO oi. silica, 666-5 almtminias, 1 On, 
glucina 14°1=100. Hmerald contains less than one per 
cent. of chromium oxide. B.B. becomes clouded, but does 
not fuse ; at a very high temperature the edges are rounded. 
Unacted upon by acids, 
Diff. The hardness distinguishes this species from apa: 
tite; and this character, and also the form of the crystals, 
from green tourmaline. 
Obs. The finest emeralds come from Muso, near Santa Fé 
in New Grenada, where they occur in dolomite. A crystal 
from this locality, 24 inches long and about 2 inches in 
diameter, is in the cabinet of the Duke of Devonshire ; it 
weighs 8 oz. 18 dwts., and is a regular hexagonal prism. A 
more splendid specimen, but weighing only 6 oz., in the 
possession of Mr. Hope, of London, cost £500. Emer- 
alds of less beauty, but of gigantic size, occur in Siberia. 
One specimen in the royal collection of Russia measures 45 
inches in length and 12 in breadth, and weighs 163 pounds 
troy. Another is 7 inches long and 4 broad, and weighs 6 
pounds. Mount Palas in Upper Eeypt affords a less dis- 
tinct variety. 
The finest beryls (aqwamarines) come from Siberia, Hin- 
dostan and Brazil. One specimen belonging to Dom Pedro 
is as large as the head of a calf, and weighs 225 ounces, or 
more than 184 pounds troy ; it is transparent and without a 
flaw. In 1827 a fine aquamarine, weighing 35 grams, was 
found in Siberia, which is said to have “been valued at 
600,000 francs. 
In the United States, beryls of enormous s17€ have been 
obtained, but seldom transparent erystals. ‘They occur in 
granite or gneiss. One hexagonal prism from Gratton, N. 
T., weighs 2,900 pounds and measured 4 feet in length, with 
one diameter of 32 inches and another of 22; its color was 
bluish green, excepting a part at one extremity, which was 
dull green and yellow. At Royalston, Mass., one crystal has 
been obtained a foot long, and pellucid er ystals are some- 
times met with. Haddam, Conn., has afforded fine crys- 
tals (see the figure). Other localities are Barre, Fitchburg 
Goshen, Mass.; Aibany, Norwich, Bowdoinham and Top- 
ham, Me.; Wilmot, N. H.; Monroe, Portland, Haddam, 
Conn.; Leiperville, Penn. 
