Page:Popular Science Monthly Volume 21.djvu/823

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THE PROGRESS OF AMERICAN MINERALOGY.

dred supposed new American minerals. Of these, perhaps one quarter are new to science, and the remainder have either been proved to be identical with species already described, or their characters are so imperfectly given that further investigation is needed to ascertain what they are. Among these new minerals are some of great interest to science. . . .

In comparing the minerals found in America with those of Europe, although interesting minor variations are observed, it can hardly be expected that very marked differences should exist. This is, of course, due to the fact that, in the inorganic kingdom, Nature has everywhere to do with the same elements, under essentially like conditions. A large number of remarkable analogies between the minerals of the two continents will occur to anyone familiar with the subject, as, for example, the character of the occurrence of individual minerals in the rocks of the Northeastern United States and Canada as compared with those of Norway and Sweden, and numberless instances of like association of minerals in various parts of Europe find their counterparts here.

A marked feature of American minerals is the grand scale upon which crystallization has taken place, individual crystals of large size being very common. The granite veins of New England afford striking examples of this kind. We have common mica, in sheets a yard across; feldspar has been observed where a single cleavage-plane measured ten feet; gigantic hexagonal prisms of beryl, four feet long and more than two feet in diameter, and weighing over two tons, have been described; spodumene crystals, six to seven feet in length and a foot or more across, and masses of rock-crystal of immense size, have been found. Canada and New York have given crystals of apatite, phlogopite, and sphene, which for these species are of marvelous grandeur in dimensions. Many other American localities might be mentioned where giant crystals occur. While it is true that these are extraordinary instances, it is also true, as a general fact common to a very large proportion of the minerals found in this country, that the species occur in much larger crystals than those obtained from European localities.

Another point worthy of note is the occurrence in comparatively large quantities, and over wide areas, of some of the rarer elements as constituents of the minerals found. In illustration of this we have, among the rare earths, glucina combined with silica and alumina in the mineral beryl, occurring in large quantity and perhaps in a hundred or more places; zirconia, in the mineral zircon, is also very widespread in its range of occurrence as an original constituent of the older rocks, as well as a vein-mineral; localities are known which have furnished this rare species by the hundred-weight. The cerium earths are found largely in the mineral allanite, which occurs in so many places that it may be said to be a common mineral in the United States. These earths are also found in the rare phosphate monazite, a