SELENSCHWEFELQUECKSILBER. 



Selenschwefelq'uecksilber. See Oxo- 

 riiiTE. 



Selensilbkr, Rose. See Naumannite. 



Selensulphuk, Dana, Stromeyer. A 

 compound of selenium and sulphur, resem- 

 bling the latter in appearance, but of an 

 orange or brownish colour. It occurs on 

 Vulcauo, one of the Lipari Islands, and at 

 the volcano of Kilauea, in Hawaii. 



Brit. Mus., Case 4. 



M. P. G. Upper Gallery, Wall-case 1, 

 No. 20. 



Selgem, Brochant. Sel Gemme. See 

 GE3iMERUiAr. Xames for Common Salt, 

 "from its breaking frequently into Gemm- 

 like squares," (IFoodward.) See EocK 

 Salt, 



Semeline. An orange- and citron -yel- 

 low variety of Sphene, found in glassy tra- 

 chyte, at the abbev of Laach, near Ander- 

 nach, on *the left "bank of the Rhine, bv 

 Hose, who called it Spinelline. 



Fig. 382. 



Name. From semen Jini, Unseed. 

 Semioarnelian. A name sometimes 

 given to yellow Carnelian. 



Semicompact Minej^l Pitch, Kirwan. 

 See Earthy Bitumen. 



Semi-opal, Kirwan, Jameson. A dull 

 variety of Opal, which differs from common 

 Opal by its greater opacity, and the muddi- 

 ness of its colours, its less perfect con- 

 choidal fracture, and greater hardness and 

 weight. It is of various shades of white, 

 grey, yellow, brown and green, and is more 

 or less translucent, sometimes passing to 

 translucent at the edges. Very brittle. 

 When compact, tlie fracture is flat-con- 

 choidal. 



Analysis, from Hanau, bv Stucke : 

 Silica . . . \ . 82 75 

 Peroxide of iron . . . S'OO 

 Alumina . . , . S-oO 



Lime 0-25 



Water . . . . . 10-00 



99-50 

 Localities. — English. Cornwall: at Huel 

 BuUer, near Redruth ; near St. Ives and 

 St. Just. Oakhampton, in Devonshire. — 

 Foreign. Faroe Isles. Iceland. Steinheim, 

 near Hanau. Schiffenberg, near Giessen. 



SEPTARIA. 343 



Sexarmontite, Bajia. Cubical. Occurs 

 in octahedrons, with an octahedral cleav- 

 age ; also often in cavernous masses 

 composed of capillary filaments, parallel or 

 slightly divergent. Colourless or greyish. 

 Transparent to translucent. Lustre pearlv ; 

 resinous or adamantine on the natural faces, 

 and especially so in the fracture. Streak 

 white. Strongly refracting. Fracture un- 

 even, often lamellar. H. 2 to 2-6. S.G. 5-22 

 to 5-3. 



Co7np. Teroxide of antimonv, or Sb = 

 antimony 84-32, oxygen 15-68 = 100. 



BB like Valentinite. 



Insoluble in nitric acid; soluble in con- 

 centrated muriatic acid. 



Localities. Sensa, near the sources of 

 Ain-el-Belbouch, in the province of Con- 

 stantina, in Algeria; at another mine, 

 Mimina, in saccharoid masses, granular or 

 compact, covered with octahedral crystals. 

 Perneck, in Hungary, 



Name. After H. de Senarmont, Professor 

 of Mineralogy at the Ecole des Mines, Paris. 



Sekeca Oil. The name given in some 

 parts of North America to a kind of Petro- 

 leum, Avhich exudes from the rocks, or floats 

 on the surface of springs. It was named 

 after the Seneca Indians, a tribe famous in 

 the confederacy, known as the Six Nations, 

 by v/hom the oil in Pennsylvania was dis- 

 covered and used. 



A similar oil is found in abundance at 

 Amiano, in Italy ; Burmah ; on the borders 

 of the Caspian Sea ; Trinidad. Along the 

 shore of the Kenawha, in Virginia; Ken- 

 tucky, near Seneca Lake, New York ; Duck 

 Creek, Ohio co. ; and in great abundance 

 at Oil Creek, in Venango co., Pennsylvania, 

 In the north-western part of Pennsylvania 

 there is a subterranean spring of this oil, at 

 a depth of 71 feet from the surface, yielding 

 from 400 to 1600 gallons per day. 



It is used as a medicine, both internally 

 and externally ; and is an excellent stimu- 

 lating embrocation for chilblains, chronic 

 rheumatism, affections of the joints, para- 

 Ij-sis, &c. It is also burned instead of oil 

 in lamps, and is one of the best lubricators 

 for machinery known. See Petroleum. 



Sepiolite, Glocker. See Meerschaum, 



Septaria. Rounded, and in most cases 

 somewhat flattened, nodular concretions of 

 argillaceous limestone, occurring at inter- 

 vals in most clay formations; in layers 

 parallel with the stratification. 



During the consolidation of the beds, the 

 calcareous matter contained in them ap- 

 pears to have separated from the muddy 

 z 4 



