The American journal of science and arts . cy,fracture and color,—being as clear, for the most part, as the intensi-ty of their colors will allow; free from flaws, except for a thin coat-ing at their surfaces; and where the crystal possesses any consider-able length, green at one extremity and red at the other. Theyhave a tendency to break across at distances of about the diameter ofthe prism, and with a highly conchoidal fracture so as to result infragments almost globular in shape, {gouttes de suif,) which arequite free from flaws, and of the finest water. Of these crystalsand fragments of c
The American journal of science and arts . cy,fracture and color,—being as clear, for the most part, as the intensi-ty of their colors will allow; free from flaws, except for a thin coat-ing at their surfaces; and where the crystal possesses any consider-able length, green at one extremity and red at the other. Theyhave a tendency to break across at distances of about the diameter ofthe prism, and with a highly conchoidal fracture so as to result infragments almost globular in shape, {gouttes de suif,) which arequite free from flaws, and of the finest water. Of these crystalsand fragments of crystals, I shall describe a few which appear to meto be the most interesting. No. 1, is one inch and a half of the extremity of a green Tour-maline, whose diameter equals its length. Its color is an intensegrass-green with a tinge of blue. It is regularly terminated by pol-ished faces, as represented in the annexed diagram. Inclination of FonP Common Goniometer, 133° 30 P on a? 158 12 a; on a? 158 45 a: on ^ 157 t on t 149 15 P ont 151. No. 2, is a fragment, three quarters of an inch in length, by oneinch two tenths in diameter; the extremities of which have been ren-dered flat by the lapidary. Its colors are faint; and it exhibits the 300 Mineralogical Journey. transition of pink into green. Although the green color seems topreponderate when the crystal is viewed in a line perpendicular tothe axis, yet, objects seen through it, in a direction parallel to theaxis, have a delicate pink tinge. This specimen illustrates with re-markable distinctness the property of double refraction. When it isbrought to the eye, in the last mentioned position, and a pin, or slen-der wire, is held at the distance of ten inches or a foot, two distinctimages of the pin or wire become obvious. No. 3, is a crystal two inches long, by one inch and a half in thick-ness. Its sides are coated with green Tourmaline to the depth ofabout a line,—the whole interior, from end to end, consisting of themost
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Keywords: ., bo, bookcentury1800, bookpublishernewhavensconverse, bookyear1820
