Page:Popular Science Monthly Volume 4.djvu/460

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these, a variety found near Gouverneur, in the State of New York, is distinguished by its peculiar brown color and internal structure. There is a suite of at least one hundred specimens of this variety alone, each one having been selected on account of some characteristic difference, and presenting together all the known and probably some yet undescribed crystalline faces. Some of the specimens are aggregates of crystals, one mass displaying fifty distinct terminations; others are individual crystals, frequently doubly terminated and showing the different arrangement of the planes upon the analogous and antilogous poles. The dimensions of one of these single crystals, reputed to be the largest ever found at Gouverneur, deserve a permanent record. It is four inches in height and four and a half inches through, with the rhombohedral faces of one termination almost perfectly developed, and with one rhombohedral face of the other termination four inches in width, the two other corresponding planes having been points of attachment to the rock. It is bounded by eighteen prismatic faces, all of which are perfect in form and polish.

Of the black tourmalines, there is one from Springfield, New Hampshire, which has a termination remarkable for the extreme development of the basal plane. It is 412 x 334 inches across, and almost extinguishes the primary rhombohedron. Among entirely unique specimens from Greenland, Bovey Tracey, in Devonshire, England, Haddam, Connecticut, Norway and Sweden, we might mention a group from Greenland, of fifty or sixty crystals, mostly doubly terminated, and from four to six inches in length, forming a rosette with divergent crystals.

To the finely colored red tourmalines, which are frequently cut and polished as gems, the name of rubellite is given; those from Siberia being mostly violet red, the Brazilian rose-red; the specimens from Chesterfield and Goshen, Massachusetts, are pale rose-red and opaque; those from Paris, Maine, fine ruby-red. Among these rubellites there are six from Elba, of exquisitely delicate pink-color. They are hexagonal prisms, one of which is one and a quarter inch in height and three quarters of an inch in diameter, all implanted on a base that is itself very beautiful from the contrasted groups of rock-crystal, adular, and rosettes of mica, of which it is made up. Of rubellites from Elba there are more than fifty specimens, some of them reposing upon the native rock; others are terminated detached crystals of various shades of pink—also crystals on the gangue and fine detached rubellites from Siberia. When it is remembered that the slightest imperfection in the sharpness of an edge or angle, the scratching of a single face, excludes a specimen from this cabinet, and that none are admitted which are not at the same time remarkable for size, beauty, and perfection of crystalline form, the brilliant effect of a drawer filled with these natural gems can be imagined.

More than usual interest attaches to the mineral of which I am