Page:Encyclopædia Britannica, Ninth Edition, v. 16.djvu/417

Rh MINERALOGY 399 Poo (h) 61 (figs. 380, 381) ; also columnar and granular. Cl. P perfect, Poo less perfect. H. =4; G. =3 6 to 37. Transparent or translucent ; vitreous, inclining to resinous. Yellowish white. C.c. : like alstonite. Alston Moor. 288. BISMUTO-SPH.ERITE, Bi 2 C. Small fibrous brown concretions from Neustadtel, near Schnee- berg. HYDROUS CARBONATES. 289. THERMONATRITE, Na 2 C + H 2. Right prismatic. ooP2 (d) 107 50 ; Poo (o) 83 50 ; with ooPoo (P) in rectangular tables (fig. 382). Cl. brachydiagonal, perfect. H. = 1 5; G. = 1 5 to 1*6. Colourless. B. B. like natron, but does not melt. C.c.: 50 &quot;1 soda, 35 4 carbonic acid, and 14 5 water. Natron lakes of Lagunilla in Venezuela, of Lower Egypt, and of the steppes between Urals and Altai. 290. NATRON, NajjC + lOHo. Oblique prismatic, C 57 40. artificial ; with cP 79 41 ; P 76 Cl. orthodiagonal, distinct. H. = 1 to 1 5 ; G. =1-4 to 1-5. Pellucid; vitreous. Colourless or greyish white. B.B. melts Fl S- 382 (sp. 289). easily, colouring the name yellow. C.c. : 22 soda, 15 carbonic acid, and 63 water ; but mixed with chloride of sodium and other salts. Only as an efflorescence on the ground or rocks (lava of Vesuvius and Etna) in various countries (Hungary, Egypt, Tartary), and in mineral springs and lakes. Used in the manufacture of soap, in dyeing, and in bleaching. 291. TROXA, URAO, Na,C 3 + 4H 2. Oblique prismatic. Crystals OP (T), ooPoo (Af), P (n) T-M 103 15 (fig. 383). Cl. orthodiagonal, perfect. H. =2-5 to 3; G. =21 to 2 &quot;2. Transparent to translucent. Colourless. Does not decompose in the air. Taste alkaline. C.c.: 38 soda, 40 car bonic acid, and 22 water. Fezzan and Barbary ( Trona), Lagunilla ( Urao). 292. GAYLUSSITE, Na 2 C + CaC + 5H 2. Oblique prismatic, C 78 27. Cl. ooP, imperfect; conchoidal. H. -2 5 ; G. -1 9 to 1 95. Transparent; Colourless. C.c. : 34 5 carbonate of soda, 33 6 carbonate of lime, 30 4 water, with T5 clay. Lagunilla. 293. HYDROMAGXESITE, Mg 4 C 3 + 4H 2. Oblique prismatic. ooP 88 nearly. Crystals small, rare ; also massive. H. =1 5 to 3; G. =2 14 to 2 18. Vitreous or silky. White. C.c. : 36 2 carbonic acid, 44 magnesia, and 19 8 water. Unst (Shetland), Moravia, Kumi in Negropont, Hoboken in New Jersey, and Texas in Pennsylvania. 294. AZURITE (Blue Copper), Cu 3 C 2 + H 2. Oblique prismatic, C 87 39. ooP (M) 99 32 ; - P (& ) 106 14. Crystals OP, ooP, cx&amp;gt;Poo, - P (or h, M, s, k , in fig. 384, but in another position) ; also radiated and earthy. Cl. clinodomatic (P) 59 14, rather perfect ; frac ture conchoidal or splintery H.-3-5 to 4-2; G.-37 to 3 8. Translucent or opaque ; vitre ous. Azure-blue, the earthy varieties (and streak) smalt- blue. B.B. on charcoal fuses and yields a grain of copper ; soluble with effervescence in acids, and also in ammonia. C.c. : 69 1 protoxide of copper, 257 carbonic acid, and 5 2 water. ^.,.^,0 . ^^.m,,,, ^ La ^u Moor, Chessy near Lyons, in Siberia, Moldawa in the Banat, Burra- Burra (Australia). Valued as an ore of copper. 295. MALACHITE, Cu 2 C + H 2. Oblique prismatic, C 61 50. ooP 104 20. Crystals ooP (.17), ooPoo (s), OP (P), in hemitropes (fig. 385). In general acicular, scaly, or reniform, stalactitic, and radiated fibrous. Cl. basal and clinodiagonal, very perfect. H. =3 5 to 4 ; G. =3 6 to 4. Transparent or translucent on the edges ; adamantine, vitreous, silky, or dull. Emerald anl other shades of green ; streak apple- green. B.B. and with acids like azurite. C.c. : 71-8 copper protoxide ( = 57 5 copper), 20 carbonic acid, and 8 2 water. Crystalline at Rheinbreiten- bach on the Rhine and Zellerfeld in the Harz ; fibrous Fi S- 38 5- and compact at Sandlodge in Shetland, Leadhills, Cornwall, Wales, .and Ireland, at Chessy in France, Siberia, the Urals, Saalfeld in Fig. 383. fracture Transparent ; vitreous. Fig. 384. Crystals at Redruth, Alston M Thuringia, Moldawa in the Banat, in North America, Africa, and Australia. Frequently pseudomorphous after copper and its ores, also after calcite and cerussite. Valuable ore of copper ; the finer varieties are prized for ornamental purposes. 296. HYDROZINCITE, ZnC + 2ZnH 2. Massive. C.c.: zinc oxide 75 3, carbonic acid 13 6, water 11 1. Spain, Westphalia, Bavaria, Persia, United States. Valuable ore. 297. AURICHALCITE, 2CuC + 3ZnH 2. Acicular. H. =2. Translucent, pearly, and verdigris-green. C.c. : 29 2 copper protoxide, 447 zinc oxide, 16 2 carbonic acid, and 9 9 water. Leadhills, Matlock, Loktevski in the Altai. 298. EMERALD-NICKEL (Zaratite), NiC + 6H 2. Amorphous, reniform, and incrusting. H. =3; G. =2 &quot;6 to 27. Translucent; vitreous. Emerald-green. C.c.: 59 3 nickel pro toxide, 117 carbonic acid, and 29 water. On chromite at Hagdale in Unst, Texas in Pennsylvania ; also Cape Ortegal in Spain, Tyrol, and Ekaterinburg in the Urals. 299. LIXDAKERITE, U 2 C + 2CaC + 10H 2. In small siskin-green crystalline aggregates. H. =2 5 to 3. From Elias mine near Joachirnsthal, implanted on pitch-blende. 300. VOGLITE, Rhomboidal. Emerald-green scales with pearly lustre. Elias mine, Joachimsthal. 301. LIEBIGITE, 2 2. Mammillary concretions. H. =2 to 2 5. Apple-green. Adrian- ople, Joachimsthal, and Johann-Georgenstadt. 302. BISMUTHITE, Bi 4 C 3 Disseminated, investing or acicular ; fracture conchoidal or un even ; very brittle. H. =4 to 4 5 ; G. =6 8 to 6 91. Opaque ; dull vitreous. Grey, yellow, or green. C.c.: 90 1 bismuth oxide, 6 4 carbonic acid, and 3 5 water. Ullersreuth (Reuss), Schneeberg, Johann-Georgenstadt ; also Chesterfield in South Carolina. 303. LANTHANITE, LaC + 3H.&amp;gt;. Right prismatic. oP 92 46. Small tabular crystals ; usually granular or earthy. Cl. basal. H. =2 ; G. =27. Dull or pearly. White or yellowish. C.c. : 21 carbonic acid, 55 lanthanum oxide, and 24 water. Bastnaes in Sweden, Lehigh in Pennsylvania. CARBONATES WITH HALOID SALTS, &c. 304. PHOSGENITE, PbCl + PbC. Pyramidal. P 113 56. Crystals short-prismatic or sharp- pyramidal. Cl. ooP, rather perfect ; fracture ^ - 7- - -^^ conchoidal. H.=2 5 to 3; G. =6 to 6 2. Transparent or translucent ; resinous adaman tine. White, yellow, green, or grey. C.c. grey. of lead. 51 chloride and 49 carbonate of le ad. Very rare. Stottfield near Elgin in Scotland, Matlock and Cromford in Derbyshire, Tar- nowitz. Fig. 386. 305. PARISITE, 3CeC + CaF. Hexagonal. P 164 58. Cl. basal, perfect. H. =4 5; G. = 4 &quot;35. Vitre ous ; on cleavage - plane pearly. Brownish yellow, inclining to red. C.c. : 23 5 carbonic acid, 42 - 5 prot- Fig 387 (sp 305) oxide of cerium, 8 &quot;2 lanthanum oxide, 9 6 dulymium oxide, 2 8 lime, 10 I fluoride of calcium, and 2 2 fluoride of cerium. Emerald mines of the Muzo Valley in Colombia, Urals. 306. LEADHILLITE (Maxite), Pb 18 C,,S 5 51 + 5H 2. Right prismatic. P middle edge 137; &amp;lt;xP 120 20 ; 2poo 43 12. Fig. 388. Fig. 389. Mostly tabular ; also twins. Cl. basal, perfect ; slightly brittle. H. =2 5 : G. =6 26 to 6 44. Transparent or translucent ; resinous