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Books Books 1 - 10 of 10 on ... veins." In the very large pegmatites the mica is not in general evenly distributed....
" ... veins." In the very large pegmatites the mica is not in general evenly distributed through the mass, but is richer in one portion than another, so that the entire bulk of the rock does not have to be removed in mining. "
Bulletin - United States Geological Survey - Page 602
by Geological Survey (U.S.) - 1910
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Proceedings of the Good Roads Institute, Held at the ..., Volumes 1-15

Good Roads Institute, Chapel Hill, N.C. - Roads - 1897
...areas. Where the pegmatite is in contact with hornblende gneiss, the latter may be highly biotitic. Pegmatites occur in irregular masses, streaks, lenses,...yards in thickness. The limit of size below which they cannot be profitably worked for mica might be placed arbitrarily at from 1 to 2 feet for rich and regular...
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Bulletin, Issues 313-315

Geology - 1907
...areas. Where the pegmatite is in contact with hornblende gneiss, the latter may be highly biotitic. Pegmatites occur in irregular masses, streaks, lenses,...profitably worked for mica might be placed arbitrarily at from 1 to 2 feet for rich and regular "veins." In the very large pegmatites the mica is not in general...
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Contributions to Economic Geology, 1906: Metals and nonmetals, except fuels

Edwin Clarence Eckel, Samuel Franklin Emmons - Geology, Economic - 1907
...areas. Where the pegmatite is in contact with hornblende gneiss, the latter may be highly biotitic. Pegmatites occur in irregular masses, streaks, lenses,...profitably worked for mica might be placed arbitrarily at from 1 to 2 feet for rich and regular "veins." In the very large pegmatites the mica is not in general...
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Congressional Serial Set

United States - 1908
...commonly occurs in overlapping lenticular-shaped bodies and sheets of more persistent extent. The deposits range from a fraction of an inch up to many yards in thickness, and the length of the lens-shaped masses may be from two or three times to more than twenty times their...
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Mineral Resources of the United States, Part 2

United States. Bureau of Mines - Mineral industries - 1908
...commonly occurs m overlapping lenticular-shaped bodies and sheets of more persistent extent. The deposits range from a fraction of an inch up to many yards in thickness, and the length of the lens-shaped masses may be from two or three times to more than twenty times their...
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Bulletin, Issue 708

Geology - 1922
...of hornblendic gneisses and schists, and in the Carolina gneiss, which is nonhornblendic, he says: Pegmatites occur in irregular masses, streaks, lenses,...fraction of an inch up to many yards in thickness. * * * Horses, or inclusions of wall rock, are common in pegmatite. Some of them are in the form of...
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High-grade Clays of the Eastern United States: With ..., Volume 8, Issue 708

Heinrich Ries, William Shirley Bayley - Clay - 1922 - 314 pages
...hornblendic gneisses and schists, and in the Carolina gneiss, which is nonhornblendic, he says: fegmaliles occur in irregular masses, streaks. lenses, augen,...balls, some of them having no visible connection with oilier pegmatite bodies. They range from :i fraction of an inch up to many yards in thickness. * *...
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Congressional Serial Set

United States - 1907
...areas. Where the pegmatite is in contact with hornblende gneiss, the latter may be highly biotitic. Pegmatites occur in irregular masses, streaks, lenses,...•worked for mica might be placed arbitrarily at from 1 to 2 feet for rich and regular "veins." In the very large pegmatites the mica is not in general...
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Bulletin, Issues 28-31

Forests and forestry - 1921
...series of hornblendic gneisses and schists, and in the Carolina gneiss which is nonhornblendic, he says: Pegmatites occur in irregular masses, streaks, lenses,...fraction of an inch up to many yards in thickness. . . . Horses, or inclusions of wall rock, are common in pegmatite. Some of them are in the form of...
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Mineral Resources of the United States, Part 2

United States. Bureau of Mines - Mineral industries - 1911
...irregular masses, streaks, and lenses which. range from small size to many yards in thickness and length. The limit of size below which they can not be profitably...for mica might be placed arbitrarily at 1 to 2 feet in thickness for rich and regular "veins." In the very hirge pegmatites the mica is not evenly distributed...
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