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| Full Text: | MINERALOGY 449 Sphalerite (ZnS) The outstanding occurrence of sphalerite in Pennsylvania is at Friedensville, where zinc ores were mined over ~ period of years. This deposit is described in detail in the chapter on Mineral Resources. Small particles of sphalerite have been reported also from some of the limonite mines in Saucon Valley, particularly from the Greene Mine, slightly less than one mile east of Lanark. On May 20, 1933 the writer found a greenish-yellow sphalerite associated with crystalline dolomite within a grayish-white chalcedony lens in an old limestone quarry a short distance southwest of the junction of the Little Lehigh and Jordan creeks, South Allentown. The limestone belongs to the Allentown formation. Other similar discoveries will doubtless be made. Halides Fluorite (CaF2) Fluorite has been noted by the writer and others in numerous places throughout the State, especially in calcite or dolomite veins in the limestones. Most of it is purple, but the light green variety has also been found. In recent years both purple and green fluorite have been found in calcite veins in the Ormrod quarries of the Lehigh Portland Cement Co. It is probably this same locality that furnished the specimens analyzed and described by E. F. Smith in the following quotation: About one and a half miles southeast of the above locality (Ironton iron mines) are the limestone quarries of Mr. Kieckner. In them have been discovered veins of beautiful fluorite and fine quartz crystals. The former mineral occurs intimately mixed with the limestone, and presents itself in the most beautiful green, purple and pink colors. Upon several' specimens octahedral forms were observed, but not very distinct. It is seldom that entire crystals can be procured, since blasting is invariably necessary to reach them; consequently fragments are the result. Quantitative analyses of the purple and green varieties were made. Purple variety: Fl 49.20 per cent. Ca 50.87 Fe,O, .. . ...... trace 100.07 The mean of the specific gravities of five specimens was 3.21; ranging from 3.17-3.24. The shade of purple varied very much in the specimens examined. Green variety: Fl 49.0.0 per cent. Ca 50.91 Fe20, trace 99.91 Sp. gr. about the same as in case of the purple. South of Emmaus in the Lehigh mountains Mr. Benj. Sadtler, Jr., found this mineral in perfect octahedra of deep purple color in a granitic rock. (Smith, 1883, p. 272.) The rather widespread but sporadic occurrence of small particles of fluorite in both the pre-Cambrian and Paleozoic strata of the State brings up the question of its origin. Although at the present time there seems to be a preference among geologists for the belief in magmatic waters as the source, the writer strongly inclines to the belief that most, if not all, the occurrences of fluorite in limestone known to him within the State have been formed by artesian waters of meteoric origin. |
| Collection: | Pennsylvania Geological Survey |
| Series: | Fourth Series, Bulletin C 39 |
| Book: | Lehigh County Pennsylvania Geology & Geography |
| Imprint: | Harrisburg, Pa.: Dept. of Internal Affairs, Topographic and Geologic Survey, 1941. |
| Section: | Mineralogy |
| Author: | Benjamin L. Miller |
| Co-Author: | |
| Project Source: | Lehigh University Digital Library Projects |
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