 | Geological Survey (U.S.) - 1905 - 530 Seiten
...portions of test tunnels in these copper- and gold-bearing intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration,...thin section shown in one of the photomicrographs (PI. XXVII, B). The reason for the decrease in assay values of copper along certain open and water-bearing... | |
 | 1905 - 848 Seiten
...portions of test tunnels in these copper- and gold-bearing intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration,...continuance of that process and replacement by black copper-sulphide. Although the illustration fails to bring them out, rims of a blue-black metallic sulphide... | |
 | William Harvey Emmons - 1913 - 274 Seiten
...The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration, and thin rima of a dark grayishblack metal about chalcopyrite observed...process and replacement by black copper sulphide. Runs of a blue-black metallic sulphide occur around grains of chalcopyrite. The reason for the decrease... | |
 | Geological Survey (U.S.) - 1913 - 272 Seiten
...portions of test tunnels in these copper and gold bearing intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration, and thin rims of a dark grayishblaek metal about chalcopyrite observed under the microscope suggest continuance of that process... | |
 | Ulysses Sherman Grant, Daniel F. Higgins - 1913 - 800 Seiten
...portions of test tunnels in these copper and gold bearing intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration, and thin rims of a dork grayishblack metal about chalcopyrite observed under the microscope suggest continuance of that... | |
 | William Harvey Emmons - 1917 - 574 Seiten
...portions of test tunnels in these copper and gold bearing intruslves. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration,...process and replacement by black copper sulphide. Rims of a blue-black metallic sulphide occur around grains of chalcopyrite. The reason for the decrease... | |
 | Geological Survey (U.S.) - 1917 - 572 Seiten
...bearing intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of aiteration, and thin rims of a dark grayish-black metal about...process and replacement by black copper sulphide. Rims of a blue-black metallic sulphide occur around grains of chalcopyrite. The reason for the decrease... | |
 | Geological Survey (U.S.) - 1905 - 522 Seiten
...gold-bearing intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteratioh, and thin rims of a dark grayishblack metal about chalcopyrite...thin section shown in one of the photomicrographs (PI. XXVII, B). The reason for the decrease in assay values of copper along certain open and water-bearing... | |
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... intrusives. The brilliant tarnish of grains of chalcopyrite indicates a beginning of alteration, and thin rims of a dark grayishblack metal about chalcopyrite observed under the microscope suggest continuance of that process and replacement by black... 