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 . croclinespecies is identical with orthoclase. Magnificent specimens havebeen obtained from Pikes Peak, Colorado, and its frequent asso-ciation with albite is noticeable, the albite crystals being implantedover it in roof-shaped flat plates. Tourmaline is a species of interest and beauty; its wellmarked crystalline form, its contrasted terminations at opposite endsof the crystal, its variety and disposition of color, and its electricalpr
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 . croclinespecies is identical with orthoclase. Magnificent specimens havebeen obtained from Pikes Peak, Colorado, and its frequent asso-ciation with albite is noticeable, the albite crystals being implantedover it in roof-shaped flat plates. Tourmaline is a species of interest and beauty; its wellmarked crystalline form, its contrasted terminations at opposite endsof the crystal, its variety and disposition of color, and its electricalproperties, developed either by friction or heat, give it a promi-nent mineralogical position. The crystals have a characteristicthree-sided appearance, from the development of the trigonalprism, and are much rounded by vertical striations; the rhombo-hedral terminations are also conspicuous. Many beautiful shadesof color are seen in tourmaline, and the singular combination ofthe red cores and green coating from Brazil, the delicate pinkcrystals from Elba and their association with quartz, the blackprisms from Norway and New York, the rich brown specimens. a ?, > •*- ^ c w o CO c -^ < -^
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmineral, bookyear1912
