PITTK^EEZ. 



Analysis, from Sch\yarzenberg, by Ram- 

 melsberg : 



Arsenic acid . . . 2670 

 Sulphuric acid . . . 13-91 

 Peroxide of iron . . . 34-85 

 Water 24-54 



lUO-00 



BB on charcoal, swells up, gives off 

 strong arsenical odours, and fuses into a 

 porous, dark reddish-brown slag, and ulti- 

 mately to a blackish magnetic globule. 



Dissolves readily in warm muriatic acid, 

 less easily in nitric acid. 



Localities. In several old mines near 

 Freiberg and Schneeberg, in Saxony. Pless, 

 in Upper Silesia. Bleistadt, in Bohemia. 

 Brittany. Chili, 



Pitticite is supposed to result from the 

 decomposition of Iron Pyrites, and is a re- 

 cent product. 



Name. From its pitch-like appearance 



(from fria-a-M^ Or iTiTTo.^ pitch). 



Brit. Mus., Case 56. 



M. P. G. Principal Floor, Wall-case 19. 



PiTTiNEKZ. PiTTiNiTE, Breithaupt. A 

 variety of Pitchblende (probably the result 

 of alteration) occun-ingin amorphous, opaque 

 masses of a pitch-black hue. Lustre highly 

 resinous. Streak greenish-brown. Fracture 

 uneven and slightly couchoidal. H. 4. S.G. 

 5-16. 



Locality. Joachimsthal, in Bohemia. 



Plagionite, G. Rose. Oblique, Occurs 

 in thick, tabular, oblique four-sided prisms : 

 also massive and granular. Colour dark 

 lead-grey. Opaque. Lustre metallic. Brittle. 

 H. 2-5. S.G. 5-4. 



Coinp. Sulphantimonite of lead, or 4Pb 

 S + SbS3 = lead 41-15, antimony 38-28, 

 sulphur 20-57 = 100. 



Fig. 337. 



Analysis, from Wolfsberger Mine, by Ku- 

 dernatsch ; 



Lead . 

 Antimony . 

 Sulphur 



. 40-98 

 . 37-53 

 . 21-49 



10000 

 BB decrepitates violently, and fuses easily, 



giving off fumes of sulphur and oxide of 



antimony. 

 Localities. Wolfsberg in the Harz, on 



PLATINA. 291 



Quartz or in drusy cavities in massive Pla- 

 gionite. 



Name. From TX,kyto;, oblique; in allusion 

 to the very oblique form of the crystals. 

 Brit. Mus., Case 11. 



Plakodine, Breithaupt, Dufrenoy. Ob- 

 lique. Occurs in tabular, attached and 

 sometimes intersecting crystals. Colour 

 bronze-yellow, somewhat paler than Magne- 

 tic Pyrites. Streak black. Very brittle 

 H. 5 to 5-5. S.G. 7-98 to 8-06. 



Fig. 338. 



Comp. Sub -arsenide of nickel, or Ni2 As 

 : nickel 60-94, arsenic 39-06 = 100. 

 Analysis, by Plattner : 



Arsenic 



Nickel . 



Cobalt . 

 Iron 

 Copper . 

 Sulphur 



39-71 

 57-05 

 0-92 

 trace 

 0-86 

 0-62 



99-16 



BB on charcoal, fuses readilv, and emits 

 arsenical fumes: after roasting, yields a 

 blue glass with borax. 



Forms a green solution in nitric acid. 

 _ Locality. The Jungfer Mine, near Miisen 

 m Siegen, Prussia, with Siderite and Gers- 

 dorffite. 



Name. From ^>^ciy,cid7i;, a table. 



Plasbia. a faintly translucent Chalce- 

 dony, in which many ancient gems are en- 

 graved. Colour grass-green or leek-green, 

 sprmkled with yellow and Avhitish specks, 

 and possessing a glistening or waxy lustre! 



Localities. India and China, Among the 

 ruins of Eome, Olympus, Schwarzwald, 

 near Baden, Hauskopf, near Oppenau. 



Name. From ^Aa<r^oj, an image. 



Brit. Mus., Case 23. 



M. P. G. Horse-shoe Case, No. 675. 



Plaster of Paris. See Gypsum. 

 _ Plata Azul. The name by which a 

 rich ore of silver, found in great abundance 

 at Real de Catorce in Mexico, is known to 

 the miners of that countrv. It is considered 

 by Hausmann to be identical with Selbite. 



Plata Verde. Bromic Silver. See Bro- 

 myrite. 



Platina. See Native Pi^itinum 

 u2 



