Page:Encyclopædia Britannica, Ninth Edition, v. 16.djvu/411

Rh MINERALOGY 393 fumes to a white, brittle, metallic globule. C.c. : 43 6 nickel and 56 4 arsenic. Hilderston in Linlithgow, Pibble in Kirkcudbright, Leudhills, Pengelly and Huel Chance in Cornwall, Freiberg, Schnee- berg, Joachimsthal, Sangerhausen, Audreasberg, Chatham in Con necticut. Used as an ore of nickel. 184. BREITHAUPTITE (Antimonial Nickel], NiSb. Hexagonal ; P 86 56 . Crystals, thin striated hexagonal tables of OP, oo P. II. - 5 ; G. - 7 5 to 7 6. Brilliant. Light copper-red, generally with violet tarnish. B. B. fumes, but fuses with great difficulty. C.c. : 32 2 nickel and 67 8 antimony. Andreasberg. 185. STANNITE (Tin Pyrites), 2CuS, SnS 2 + 2(FeS, ZnS) + SnS 2 . Cubic ; in cubes very rare, generally massive and granular. Cl. hexahedral, imperfect ; fracture uneven or small conchoidal ; brittle. H. =4 ; G. =4 3 to 4 5. Steel-grey ; streak black. C.c.: 26 to 32 tin, 24 to 30 copper, 5 to 12 iron, 2 to 10 zinc, and 30 sulphur. Huel Rock near St Agnes, St Michael s Mount, and Cam- brea in Cornwall; Zinuwald. Bell-metal ore. 186. STERNBERGITE, (AgS + 2FeS)FeS 3 . Right prismatic; P middle edge 118. Crystals usually thin tabular; in twins, or in fan-like and spheroidal groups. Cl. basal, perfect ; sectile, and flexible in thin laminae. H. = 1 to 1 5 ; G. = 4 2 to 4 25. Dark pinchbeck-brown, often a violet-blue tarnish ; streak black. C.c. : 34-2 silver, 35 &quot;4 iron, and 30 &quot;4 sulphur. Joachimsthal, Schnecberg, and Johann-Georgenstadt. Flexible Sidphurct of Silver, from Hungary and Freiberg, is identical. Frie- seite, Ag 2 Fe 5 S 8, in twins (fig. 339), is a variety. 187. RlTTINGERITE, AgAs. Oblique prismatic, oop 126 18 ; ooPoo and OP. Cl. basal ; fracture conchoidal; brittle. H. =2 5to3; G. =5 63. C.c. : silver 577, the remainder being arsenic, with some selenium. Joachimsthal, Silesia, Felsb banya in Hungary. 188. COVELLINE, CuS. Hexagonal. Crystals ooP, OP; rare; usually reniform and granu lar. Cl. basal; sectile. Thin laminse flexible. H. =1 5 to 2 ; G. =- 3 8 to 4 6. Resinous. Indigo-blue; streak black. B. B. burns with blue flame. Sol. in n. acid. C.c.: 66 7 copper, 33 3 sulphur. Cairnbeg in Cornwall, Vesuvius, Leogang (Austria), Chili, Angola, New Zealand, and Victoria. 189. CHALCOPYRITE (Copper Pyrites), CuS + FeS. Pyramidal ; and sphenoidal hemihedric ; P (P) with polar edges 71 20 ; ooPoo. Crystals generally small and deformed; twins very common, like fig. 340. P=c (6) 89 10, 2Po(c) 126 11 , OP (a), P (fig. 89). Most commonly compact and disseminated; also botryoidal and reniform. Cl. pyramidal 2Poo ; some times rather distinct; fracture conchoidal or uneven. H. =3 5 to 4; G. = 4 1 to 4 3. Brass-yellow, often with a gold-yellow or iridescent tarnish (peacock copper ore) ; streak greenish black. B. B. on charcoal be comes darker or black, and on cooling red; fuses easily to a steel-grey globule, which at length becomes magnetic, brittle, and greyish red on the fractured surface ; with borax and soda yields a grain of copper; moistened with h. acid, colours the flame blue. C.c. essenti ally 1 atom copper, 1 atom iron, and 2 atoms sulphur; with 34 5 copper, 30 5 iron, and 35 sulphur. The most abundant ore of copper. In Kirkcudbright shire and Wigtownshire, Tyndrutn in Perthshire, Inverness-shire, Lairg in Sutherland, Shetland, Anglesea (Parys mine), Derbyshire, Staffordshire, Cumberland, Gunnislake (Devonshire), St Austell (Cornwall), Wicklow, Falun, Rb raas, Freiberg, Mansfeld, Goslar, Lauterberg, Mtisen, Siberia. It is distinguished from pyrite by yielding readily to the knife, by its tarnish, and by forming a green solution in n. acid. 190. BORNITE (Purple Copper), 3Cu 2 S, Fe 2 S 3. Cubic. Crystals ooOoo, and ooOoo, 0; but rare, and generally rough or uneven ; also twins. Mostly massive. Cl. octahedral ; fracture conchoidal ; slightly brittle ; sectile. H. = 3 ; G. = 4 &quot;9 to 5 1. Colour between copper-red and pinchbeck-brown, with tarnish at first red or brown, then violet or sky-blue ; streak greyish black. B. B. acts like chalcopyrite. Soluble in con. h. acid, leaving sulphur. C.c. : 55 6 copper, 16 &quot;4 iron, and 28 sulphur. Crystals near Redruth and St Day in Cornwall ; massive at Killarney in Ireland ; also Norway, Sweden, Mansfeld, Silesia, Tuscany, and Chili. An ore of copper. 191. CUBAN, CuS, Fe 2 S 3. Cubic. H. =4; G. =4*1. Bronze-yellow; streak bronze-yellow and black. Barracanao in Cuba, Tunaberg and Kafveltorp in Sweden. 192. DOMEYKITE, Cu 6 As. Botryoidal or massive ; fracture uneven ; brittle. H. =3 to 3 5 ; G. =7 to 7 5. Tin- or silver- white, inclining to yellow, with an iridescent tarnish. Not affected by h. acid. C.c. : 71 63 copper and 28 37 arsenic. Calabazo in Coquirnbo, and Copiapo in Chili. Coii- durritc,ma.ssive, seems an impure variety ; from Condurrow mine and near Redruth (Cornwall). Algodonitc from Lake Superior, Whit- neyite from Mexico, and Darwinite (88 copper) are also identical or similar. 193. MELONITE, Ni 2 Te 3. Hexagonal ; minute tabular crystals, foliated and granular. Metallic lustre. Reddish white; streak dark grey. C.c. : nickel 21, silver 4 1, tellurium 73 4. Stanislaus and Calaveras (California). 194. SYLVANITE, AgTe 4 + AuTe 3. Oblique prismatic, C 55 21. ooP 94 26 ; - Poo 19 21 ; Foo 62 43 . Crystals small, short acicular, and often twinned and grouped in rows like letters; sectile, but friable. H. = T5 to 2; G. =7 99 to Fig. 343 (sp. 195). Fig. 341. Fig. 342. 8 33. Steel-grey to silver-white, and pale bronze-yellow. C.c. : 59 6 tellurium, with 6 to 8 5 antimony, 26 &quot;5 gold (in some 30), and 13 9 silver, with 2 to 15 lead. Oifenbanya (Graphic Tellurium), Nagyag ( Yellow Tellurium), and California. 195. NAGYAGITE, Black Tellurium. Pyramidal. P 137 52 ; Poo 122 50 ; and OP (fig. 343). Crystals tabular, rare; in general in thin plates or foli ated. Cl. basal, perfect; sectile; thin laminae flexible. H.=l to 1-5; G. = 6 85 to 7 &quot;2. Splendent. Blackish lead-grey. C.c.: 51 to 63 lead, 6 to 9 gold, 1 copper and silver, 13 to 32 tellurium, 3 to 12 sulphur, and to 4 5 antimony. Nagyag and OfTenbanya in Tran sylvania. 196. MALDONITE, Au 2 Bi. H.-1-5 to 2; G. =8-2 to 97. Colour silver-white, with black tarnish. C.c.: gold 64 5, bismuth 35 &quot;5. Occurs in granite veins at Maldon in Victoria. 197. CHILEXITE, Ag 10 Bi. Minute plates of metallic lustre. Silver-white, but tarnished r.-d or yellow. Silver 83 &quot;9, bismuth 16 -1. From the mine Saa Antonio near Copiapo in Chili. 198. CINNABAR, HgS. Hexagonal and rhombohedral; R7148. R (n), OR (o),ooR (m], ?R (L) (fig. 344). Crystals rhombohedral; also granular, compact, and earthy. Cl. ooR, perfect ; fracture uneven and splintery ; sectile. H. =2 to 2 &quot;5; G. - 8 to 8 2. Trans parent, with circular polarization. Adaman tine. Cochineal-red; streak scarlet. C.c.: 86 2 mercury, 13 8 sulphur. Iilria in Carniola, Almaden in Spain, Wolfstein in Bavaria, Saxony, Hungary, Tuscany, China, Cali fornia, Mexico, Peru. Chief ore of mercury. Hepatic Cinnabar is a bituminous mixture. 199. TIEMANNITE, HgSe . Finegranular ; brittle. H. =2 5; G. =7 1 to 7 4. Brilliant. Dark lead-grey. C.c.: 75 mercury, 25 selenium. Clausthal and Zorge. 200. LERBACHITE, (PbHg)Se . Granular and massive. G. =7 8 to 7 88. Colour steel-grey to iron-black. Brittle. Lerbach, Tilkerode in the Harz. 201. GUANAJUATITE, BLSe 3 . Massive ; granular ; foliated and fibrous. II. = 2 - 5 to 3 ; G. = 6 25. Blue-grey; streak grey and shining. Metallic; soft and malleable. C.c. : selenium 34 3, sulphur 7, bismuth 65. Santa Rosa (Guana juato, Mexico). XVI. 50 Fig. 344. Also a pigment.