A New System of Mineralogy in the Form of a Catalogue (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1799 edition. Excerpt: ... ( ) obtained, are thofe of Saska in the BannaU Johngeorgenstadt and Eibenstock in Saxony, and Joacbimsthal in Bohemia. VARIETY I. CRYSTALLISED. . a 1. In thin Tectangular plates, of a straw yellow colour, on an ochry micaceous indurated schistus. Johngeorgenstadt. II. a 2. The fame, in more minute plates of a grass green colour changing to a greenish yellow, on coarse ferruginous quartz. Same place. III. a j. The fame, of a perfect: grass green colour, some of the crystals of sufficient thickness to become cubic, on an ochry indurated clay intermixed with quartz and mica. Same place. IV. b i. In indeterminate crystals of the fame colour, on black compact scaly pechblende somewhat shining in its fracture. Same place. VARIETY II. AMORPHOUS. V. a 1. Of an earthy texture and yellowish white colour, on the surface of pechblende. Georgewagsford, Saxony. SPECIES II. SULPHURET OF URANITE. Pecbblende, Fr. Scbwarz-Uranerz, Emmerling. There is but little variety in the colours and forms of this ore, being generally of different shades of greyish black, and found for the most part in lumps, or interspersed, sometimes cellular, very rarely reniform, and never crystallised. It is sometimes iridescently tarnished on the surface; always opake. Its lustre internally semi-metallic inclining to the unctuous and sometimes to that of the diamond. Its fracture conchoidal approaching to the uneven; brittle; not of sufficient hardness to give fire with steel; streak darker coloured; specific gravity 7.500. Its metallic part dissolves most readily in the nitric acid or in aqua regia, yielding solutions of a pale yellow colour. Under the blowpipe it is infusible per se; with soda or borax it gives a grey opake slag, and with microcofmic falt a clear glass of a...