MINERALS INDEX
Gypsum |
| CaSO4.2H2O |
| Monoclinic |
Gypsum was identified in a single specimen, given to the author at Franklin, which shows a secondary carbonate vein in massive ore. The filling is chiefly calcite in coarse curved lamellae which, where they reach the vein cavities, are covered with radiate acicular crystals of calcite in parallel position to the underlying calcite. Lying across the ends of the slender crystals of calcite and but lightly attached to them are several clear, colorless crystals of gypsum, the largest a fifth of an inch long. The crystals have rounded faces owing to solution and are not measurable but appear to be bounded by ordinary forms. In the same cavities are masses of honey-yellow willemite of curious platy form.
Gypsum was found in 1927 at Sterling Hill on the 1,100-foot level. The single specimen in hand shows a veinlike mass of selenite consisting of a single crystal with perfect cleavage. The specimen is too small to show the true relation of the gypsum to the granular ore which it cuts.
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© by Herb Yeates 1997-2006.
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page created: August 12, 2006 6:21 PM
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