 | Good Roads Institute, Chapel Hill, N.C. - Roads - 1897 - 1172 pages
...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... | |
 | Geology - 1907 - 1026 pages
...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... | |
 | Geology, Economic - 1907 - 532 pages
...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... | |
 | United States - 1908 - 916 pages
...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... | |
 | United States. Bureau of Mines - Digital images - 1908 - 906 pages
...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... | |
 | Charles Willard Hayes - Coal - 1910 - 764 pages
...areas. Where the pegmatite is in contact with hornblende gneiss, the latter may be highly biotitic. Pegmatites occur in irregular masses, streaks, lenses,...to many yards in thickness. The limit of size below wluch they can not be profitably worked for mica might be placed arbitrarily at 1 to 2 feet for rich... | |
 | Geology - 1922 - 434 pages
...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... | |
 | Heinrich Ries, William Shirley Bayley - Clay - 1922 - 404 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. * *... | |
 | North Carolina. Department of Conservation and Development - Geology - 1925 - 298 pages
...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... | |
 | North Carolina. Division of Mineral Resources - Geology - 1925 - 138 pages
...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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... 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. 
