Transactions . Silver of James Township 265 feldspathic material. In the thin sections examined by him,representing several of these veins from the western part of Tud-hope and the central part of James township, by far the largestproportion at least was plagioclase varying in composition fromalbite through oligoclase to andesine. This diagnosis was cor-roborated in part by a separation of the mineral constituents bymeans of a heavy solution. The plagioclase thus separated variedin specific gravity from to Some of this plagioclase(albite) had distinct rectangular or lath-like outl
Transactions . Silver of James Township 265 feldspathic material. In the thin sections examined by him,representing several of these veins from the western part of Tud-hope and the central part of James township, by far the largestproportion at least was plagioclase varying in composition fromalbite through oligoclase to andesine. This diagnosis was cor-roborated in part by a separation of the mineral constituents bymeans of a heavy solution. The plagioclase thus separated variedin specific gravity from to Some of this plagioclase(albite) had distinct rectangular or lath-like outlines, showingtwinning according to both the albite and pericline laws, which incertain cases produced a fine cross-hatched structure, usuallyconsidered characteristic of the appearance of microcline betweencrossed nicols. Most of these grains are quite turbid. Anotherspecies of plagioclase (oligoclase) occurs in irregular, untwinnedand clear grains, thus resembling quartz; but unlike quartz thismineral is readi
Size: 1882px × 1328px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookcentury1800, booksubjectmineralindustries, bookyear1895
