A popular guide to minerals : with chapters on the Bement Collection of minerals in the American Museum of Natural History, and the development of mineralogy . e interior is beautifully shown; the paper and rounded pinkcalcite from Guanajuato, Mexico; the interpenetrating crystals,forming celllike partitions, and coated with quartz, from AnthonysNose, N. Y.; remarkable cabbagelike spheres of enchained rhombo-hedrons from the Yellowstone Park, Wyoming; and splendid exam-ples of Iceland spar from Iceland. With these are numerous speci-mens further illustrating the associations and varying condit
A popular guide to minerals : with chapters on the Bement Collection of minerals in the American Museum of Natural History, and the development of mineralogy . e interior is beautifully shown; the paper and rounded pinkcalcite from Guanajuato, Mexico; the interpenetrating crystals,forming celllike partitions, and coated with quartz, from AnthonysNose, N. Y.; remarkable cabbagelike spheres of enchained rhombo-hedrons from the Yellowstone Park, Wyoming; and splendid exam-ples of Iceland spar from Iceland. With these are numerous speci-mens further illustrating the associations and varying conditionsof this wonderful mineral, amongst which the curious ruin marblewill be noticed, its mimetic structure arising from faulting andcoloration by iron oxide. In the suites of specimens there is a greatvariety of examples, amongst which the Argentitc, a pearly lamin-ated calcite, the lumachella made up of fossil shells, the penetra-tion twins from England, the calcite saturated with byssolite fromFrench Creek and the superb combinations of crystals in white anddelicately colored groups are distinguished by beauty or interest. w iPF» Sterling Hill, N. AMPHIBOLE Pierrepont, New YorkBement Collection, American Museum of Natural History GUIDE TO COLLECTIONS 195 The property of double refraction possessed by a great numberof minerals is especially strong in calcite. It arises from a split-ting up of the ray of light, into two, and as each brings to the ob-server the picture or image from which it is reflected, the eye dis-cerns two images. , of many kinds are found in calciteand this produces a series of varietal forms. In large collections the calcites from Mexico occur in beautifulseries, the honey crystals from Joplin, Missouri, the large crystalsenclosing brilliant copper flakes from Lake Superior, and the end-less groups from England, with their tints from hematite admix-ture and their clear white crystals in flowerlike combinations. Dolomite, the carbonate of l
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmineral, bookyear1912
