92 COMMON FELSPAR. 



Common Felspar. See Orthoclase. 



Common Jade. See Nephrite. 



Common Mica. See Muscovite. 



Common Opal. The name applied to 

 the common varieties of Opal which do not 

 exhibit the peculiar play of colours termed 

 opalescence. 



Localities. Cornwall : at Huels Stennack, 

 Spinster, Bailer, Damsel, Poligine, Kose- 

 warne, ike, and at Botallack jNIine, Si. 

 Just. Abundantly at the Giant's Cause- 

 way in Ireland, the Hebrides, Faroe, Ice- 

 land and Hungary. A wax-yellow or 

 greyish-green variety, sometimes white, 

 occurs in Smyrna Harbour, (within half a 

 mile, in a S.W. direction, of the watering- 

 place at Vourla), with yellow^ Jasper and 

 Hornstone, imbedded in a low ridge of 

 compact pale yellow or greyish-white lime- 

 stone. 



Common Opal is sometimes made into 

 pins, cane-heads and other ornaments. 



Common Salt, Dana. See Rock Salt. 



Common Serpentine. See Serpentine. 



C031MON Spar, Kirwan, Calcareous 

 Spar. 



Compact Bitumen, Phillips. See As- 

 phalt. 



Compact Mineral Pitch, Kirwan. See 

 Asphalt. 



Compostella Hyacinth. Quartz cry- 

 stals coloured red by an admixture of 

 ferruginous clay found at Compostella. 



CoMPTONiTE, Brewster. ilhombic; is 

 found in white translucent crystals, the 

 primary form of which is a right rect- 

 angular prism, of which the base is not 

 square. Lustre vitreous. Streak white. 

 Fracture small-conchoidal and uneven. H. 

 5 to 5-5. S.G. 2-35 to 2-4. 



fO^ 



Fig. 126, 



Analysis, from Seeberg, by Rammekherg- 



Silica 38-74 



Alumina .... 30-84 



Lime 13-43 



Soda ..... 3-85 



Potash 0-54 



Water 13-10 



CONDURRITE. 



to the specimens of the latter mineral which 

 occur in the vesicular lavas of Vesuvius. 



Localities. Renfrewshire, at Kilmalcolm 

 and Port Glasgow. In basalt at the Pilaster 

 Kante, near Eisenach, in Saxe Weimar. 

 Bohemia in Clinkstone at Seeberg and Hau- 

 enstein. The Cyclopean Isles, in Sicily, Avith 

 Analcime and Phillipsite. 



Name. After Lord Compton, by whom it 

 was first distinguished. 

 Brit. Mus., Case 27. 



CoMPTONiiTC KouPHONE Spar, Haidin- 

 ger. See Cojmptonite. 



CoNARiTE, Breltkaupt. Occurs in small 

 grains and crystals, Avith one perfect clea- 

 vage. Colour yellowish, pistachio- and 

 siskin-green ; also olive-green. Translucent 

 in thin lamellae. Streak siskin-green. H. 

 2-5 to 3. b.G. 2-459 to 2-49. 



Locality. Rottis in Voigtland, with 

 Rottisite. 



Name. From yJva^o;, evergreen. 

 CoNDRODiTE, Haily. See Chondrodite. 

 CoNDURRiTE, Faraday. Is an arsenite of 

 copper derived from the oxidation or Avea- 

 theringof the arsenide Cu^ As {Domeykite). 

 It occurs mostly in no^lular masses, ex- 

 ternally of a brownish-black colour (some- 

 times Avith a tinge of blue), and earthy ; 

 internally on a fresh surface exhibiting a 

 tin-Avhite tarnish. Also black and soft, 

 soiling the lingers. Yields to the knife, 

 producing a metallic -looking surface, nearly 

 of a lead-grey colour. Brittle. Fracture flat- 

 conchoidal. H. 3 to 3-5. S.G. 4*5. 



Comp. 6Cu As + 4H = copper 70-11, ar- 

 senic 29-88-100. 



10050 

 BB froths up slightly, becomes opaque, and 

 fuses imperfectly to a vesicular glass. 



Comptonite is mereb' a variety of Thom- 

 sonite, and the name Avas originallv given 



nalysis, by J. Blyth : 





Copper 



. 60-21 



Arsenic 



. 19-51 



Iron . . . . 



. 0-25 



Sulphur 



. 2-33 



Oxygen 



. 13-17 



Carbon 



. 1-62 



Hydrogen 



. 2-41 



Nitrogen 



. 0-06 



Water . . . . 



. 2-41 



100-00 

 BB on charcoal gives off fumes of arsenious 

 acid, and yields a metallic globule of the 

 colour of copper. In a tube affords fumes of 

 arsenious acid and Avater, and Avith soda and 

 borax yields a globule of copper. 



Not soluble in muriatic acid. 



Localities.— English. CornAvall at Con- 

 durrow Mine, and at Carn Brea Mines, near 

 Redmih.— Foreign. The Cordilleras of Co- 

 piapo, Chili, S. America. 



