Ch. 6: Different Beryls in Maine

Ch. 6: Different Beryls in Maine Page of 170 Ch. 6: Different Beryls in Maine Text size:minus plus Restore normal size   Mail page  Print this page
BEBYL.                                                   145
be scratched with a knife. The color varies from emerald green through pale green, light blue, and golden yellow to white and pale pink. The crystals are generally hexagonal prisms, many of them striated vertically, and most of them terminated by a single flat plane at right angles to the long axis of the prism. Some pyramidal terminations also occur. There is no marked cleavage, only an imperfect one parallel to the basal planes. Beryl is fusible only with difficulty and is not attacked by acids.
OPAQUE BERYL.
The commoner varieties of beryl are light blue or green in color, -and are opaque, though portions of some crystals are transparent and may even yield gems. Opaque crystals are quite common in most of the coarser pegmatite deposits of Maine, where they occur as more or less regular prisms embedded in the solid pegmatite. Some of these reach remarkable dimensions; one found in the Maine Feld­spar Company's quarry at Mount Apatite in Auburn was described as having a diameter equal to that of a hogshead. One from the Noyes gem mine in Greenwood, Oxford County, was so large that a man could barely reach around it with his arms. From Acworth, N. H., one crystal 6-1/4 feet long and another estimated to weigh over 2-1/2 tons were quarried. A peculiar beryl from Auburn is described by Kunz as follows: °
In the state cabinet in Albany, N. Y., is a curious beryl found by S. C. Hatch at Auburn, Maine. It is of imperfect structure and broken diagonally across, showing the structure to advantage. It is 8-4/5inches (30 centimeters) high, 8-3/5 inches (22 centi­meters) wide, and has 50 different layers, 25 of beryl, the remaining 25 of albite, quartz, and muscovite. All the corners of the hexagonal prism are carried out in full, giving the beryl an asteriated appearance and making it a striking and interesting specimen.
The opaque varities of beryl are of little commercial value, though prized for museum collections when they show perfect crystal forms.
EMERALD.
Transparent beryl of deep-green color is the gem emerald, but it must not be confused with the oriental emerald, which is a green variety of corundum. Emeralds are of rare occurrence in the peg­matite deposits of Maine. One crystal of light grass-green color embedded in quartz was observed by the writer at the Dunton gem quarry in Newry, Oxford County. It was a prism half an inch across and 1-1/2 inches long but was so badly fractured as to be valueless for gems. Parker Cleveland b mentions having seen several emer­alds from Topsham, Sagadahoc County, of a lively green color and
o Kunz, G. F., Gems and precious stones, pp. 91-92. b Mineralogy and geology, 1822.
63096°—Bull. 445—11-----10
Ch. 6: Different Beryls in Maine Page of 170 Ch. 6: Different Beryls in Maine
Suggested Illustrations
Other Chapters you may find useful
bullet Tag
This Page