Page:Encyclopædia Britannica, Ninth Edition, v. 16.djvu/424

406 MINERALOGY 412. OLIVENITE, 4Cu ( ASjP ,) + H, . Right prismatic. oo(P) (r) 92 30 , Poo (Z) 110 (fig. 431); also spherical and reniform, and columnar or fibrous. Cl. (r} and (I), im perfect. H. = 3; G. = 4 1 to 4 6. Pellucid in all degrees ; vitreous, resinous, or silky. Leek-, olive-, or blackish-green, also yellow or brown ; streak olive-green or brown. B. B. in the forceps fuses easily to a dark brown adamantine bead, covered with radiating crystals ; on charcoal detonates, emits arsenical vapours, and is reduced. Sol. in acids and ammonia. C.c. : 56 5 copper protoxide, 39 "5 arsenic acid, and 4 water ; but also 1 to 6 phosphoric acid. Carharrack, Tin Croft, Gwennap, and St Day in Cornwall ; Alston Moor, Tlmringia, Tyrol, Siberia, Chili. 413. VESZELYITE, 9Cu, 6Zn, P 2 , As 2 + 18H 2 . Oblique prismatic, C 103 50 . H. = 3 "5 to 4 ; G. Fig. 431. = 3 53. Green ish blue. C.c.: copper 37 34, 25 20 zinc oxide, 10 41 arsenic acid, 9 - 01 phosphoric acid, 17 - 05 water. Moravicza (Banat). 414. DESCLOIZITE, 2PbV 2 + H 2 . Right prismatic. ooP 116 25 . H. =3 5; G. =5 86 to 61. Olive-brown to black. C. c. : 56 48 oxide of lead, 16 6 oxide of zinc, 116 oxide of manganese, 2274 vanadic acid. Sierra de Cordoba in the Argentine Republic. 415. VOLBORTHITE, 4(Cu, Ca) V 2 + H 2 . Hexagonal; small tabular crystals, OP, ooP, single or in groups. Generally massive. H. =3; G. =3 "45 to 3 89. Olive-green; streak almost yellow. B.B. on charcoal fuses easily and forms a graphite-like slag, containing grains of copper. Sol. in n. acid, and with water gives a brick-red precipitate. C.c. : 37 to 38 vanadic acid, 39 - 4 to 46 copper oxide, 18 5 to 13 lime, 3 6 to 5 water. Sissersk (Urals), Nijni-Tagilsk, and Friedrichroda in Thuringia. 416. TAGILITE, 4CuP 2 + 3H 2 . Oblique prismatic ; but botryoidal and radiating- fibrous, or earthy. H. =3; G. =4. Emerald-green. C.c.: 61 - 8 copper prot oxide, 27 7 phosphoric acid, and 10 "5 water. Nijni-Tagilsk, and near Hirschberg. 417. EUCHROITE, 4CuAs 2 + 7H 2 . Right prismatic. ooP (M) 117 20 , Poo (n) 80 52 , with ooP2 (1) and OP (P) (fig. 432). Brittle. H. =3 5 to 4 ; G. = 3 35 to 3 45. Translucent ; vitre ous. Emerald- or leek -green ; streak ver digris-green. B.B. in forceps fuses to a greenish brown crystallized mass. Easily sol. in n. acid. C.c. : 47 copper protoxide, 34 arsenic acid, and 19 water. Libethen in Hungary. 418. ERINITE, 5CuAs 2 + 2H 2 . . Reniform and foliated; conchoidal fracture. H. = 4 5 to 5 ; G. = 4 to 4 1. Translucent on Fl g- 432 ^ *") the edges; dull resinous. Emerald- or grass-green ; streak similar. C.c. : 59 9 copper protoxide, 347 arsenic acid, and 5 4 water. Cornwall. Cornwallite has 3 or 5 of water. 419. DIHYRITE, 5CuP 2 + 2H 2 . G. =4 4. Oxide of copper 69, phosphoric acid 247, water 6 25. Rheinbreitenbach and Nijni-Tagilsk. 420. MOTTRAMITE, 5(Cu, Pb)V 2 + 2H 2 . Black crystalline crusts ; streak yellow. H. = 3 ; G. = 5 9. C.c. : oxide of copper 20 4, oxide of lead 7 2, vanadic acid 187, water 37. Mottram in Cheshire. 421. EHLiTE5Cu P Right prismatic ; botryoidal, radiating, foliated. H. = 1 - 5 to 2 ; G. = 3 - 8 to 4 "27. Translucent on the edges ; pearly on the cleavage. Verdigris-green ; streak paler. C.c. : 67 copper protoxide, 24 phosphoric acid, and 9 water. Ehl on the Rhine, Nijni-Tagilsk, Libethen. 422. TYROLITE, 5CuAs 2 ....... Right prismatic. Cl. basal, perfect ; reniform. Radiate-folia- ccoua. H. = 1 -5 to 2; G. = 3. Lustre pearly on cleavage face. Colour apple-green and verdigris-green to sky-blue ; streak paler. Sub- translucent. C.c. : oxide of copper 50 3, arsenic acid 29 2, water 20-5. Tyrol, Hesse, Thuringia. 423. PHOSPHOROCHALCITE (Lunnite), 6CuP 2 + 3H, . Oblique prismatic. Crystals ooP c 2 (/) 38 56 , P (P) 117 49 , Fig. 433 (sp. 423). Translucent ; vitre- with OP (a) and ooPoo (c} (fig. 433) ; usually small and indistinct; more common in spherical or reniform and radiated-fibrous masses. H. = 5 ; G. = 4 1 to 4 3. Translucent throughout or on the edges; adamantine to resinous. Blackish-, emerald-, or verdigris-green. C.c. : 70 8 copper protoxide, 21 "2 phosphoric acid, and 8 water. Cornwall, Rheinbreitenbach, Nijni-Tagilsk. 424. CLINOCLASE, 6CuAs 2 + 3H 2 . Oblique prismatic, C 80 30 . OP (P), ooP(w) 56, fPoo (a) 99 30 , (r) 123 48 (figs. 434, 435) ; and hemispherical. Cl. basal, perfect. H. = 2 5 to 3 ; G. = 4 2 to 4 4. ous ; pearly on cl. Dark verdigris-green to sky-blue ; streak blue. C.c. : 62 6 copper protoxide, 30 3 ar senic acid, 71 water. Corn wall, Tavistock, Erzgebirge. 425. MIXITE. Oblique prismatic or an- orthic (?). Radiating, cen trally granular. oop 125. H. =3 to 4; G. =2-66. Eme rald-green to blue-green ; streak paler. C.c.: 43 21 . copper oxide, 13 1 bismuth Fl S 434 < S P- 424 ) ^ 435 (sp. 424). oxide, 30 45 arsenic acid, 111 water. Geistergang, Joachimsthal. 426. RHAGITE, 5Bi 2 2As 2 - Grape-like groups of minute crystals. Colour yellowish green ; streak white. Lustre wax-like ; brittle. H. =5; G. =6 82. C.c.: bismuth oxide 79 5, arsenic acid 15 6, water 4 9. Neustiidtel near Schneeberg. 427. TROGBRITE, 3UAs 2 + 12H 2 . Oblique prismatic, C 80. Crystals thin tabular. Cl. clino- diagonal, perfect. Lustre pearly. G. =3 3. Lemon-yellow. C.c.: 65 95 oxide of uranium, 17 56 arsenic acid, 16 49 water. In closed tube gives off water, and becomes golden brown, but again yellow on cooling. Neustadtel. 428. STRUVITE, (NH 4 , 2Mg) P 2 + 12H 2 . Right prismatic. Poo (a) 63 7 , Poo (c) 95, 4? oo (V) 30 32 , oopoo (), jFoo (m) 123, OP (o) (fig. 436). Cl. brachydiagonal, perfect. H. = 1 5 to 2 ; G. = 1 66 to 1 75. Trans parent or opaque ; vitreous. Colourless, but yellow or brown. C.c.: 29 9 phos phoric acid, 16 3 magnesia, 10 6 am monia, and 44 water. Under St Nicholas church at Hamburg, and in guano from South America. Fig. 436. 429. ARSENIOSIDERITE, Spherical and fibrous ; friable. H. =1 2 ; G. =3 52 to 3 "88. Opaque; silky. Golden yellowish brown; streak yellowish brown. C.c. : peroxide of iron 39 4, lime 13 8, arsenic acid 37 - 9, water 8 9. Romaneche near Macon. 430. CHALCOSIDERITE. Anorthic. Light green crystals. oxide of iron, 8 1 oxide of copper, 4 45 alumina, 30 5 4 phosphoric acid, 15 water. Cornwall. 431. LAZULITE, A1 2 F 2 per G. =311. + (Mg, Fe) 3 p 2 Oblique prismatic, C 88 2 . ooP 91 30 , P () 99 40 , - P (p) 100 20 . Crystals often tabular through distortion ; twins on OP, and ool co; also massive ; fracture splint ery. Cl. oo P. H. = 5 to 6; G. =3 to 31. Trans lucent ; vitreous. Indigo- and smalt-blue to greenish ; streak white. In closed tube yields water, and loses colour. Soluble in acids after ignition. C.c.: 317 alumina, 10 magnesia, 6 prot oxide of iron, 44 phosphoric acid, and 6 water. Salzburg, Styria, Brazil, Georgia, Lincoln in North Carolina.

437 (sp. 431). Fig. 438 (sp. 431).