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 . CYANITE Biirnsville, N. C. Bement Collection, American Museum of Natural History. ANDALUSITE Delaware Co., Collection, American Museum of Natural History DEVELOPMENT OF MINERALOGY 235 make mineralogy a chemical science, and it seems to grow con-stantly clearer that in chemical composition is to be found most ofthe determinative characteristics of mineral species. The depend-ence of physical or optical qualities upon compositio
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 . CYANITE Biirnsville, N. C. Bement Collection, American Museum of Natural History. ANDALUSITE Delaware Co., Collection, American Museum of Natural History DEVELOPMENT OF MINERALOGY 235 make mineralogy a chemical science, and it seems to grow con-stantly clearer that in chemical composition is to be found most ofthe determinative characteristics of mineral species. The depend-ence of physical or optical qualities upon composition has onlyrecently been demonstrated in a paper by Prof. Penfield, who hasshown that the varyino- inclination of the optic axes of topaz arisesfrom the varying amounts of fluorine present. It may finally be claimed that in a sense mineralogy approachesa finished science. Special investigations may extend the list ofspecies, or reveal qualities in old ones not hitherto suspected, butits broad outlines are drawn and they are solidly filled in. Thefuture development of mineralogy lies in the field of paragenesis—the associations and affinities of minerals—and in the syntheticproduction of them and their pyrogenetic history. A closer
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectmineral, bookyear1912
