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

Rh 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 &quot;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 &quot;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 &quot;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 &quot;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 ^ *&quot;) 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 &quot;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 &quot;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 &amp;lt; 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 &quot;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).