290 PISTOMESITE. 



Name. From its pistachio-green colour. 



Brit. Mus., Case 35. 



M. P. G. Horse-shoe Case, Nos. 1030 

 to 1032. 



PiSTOMBSiTE, Breithaupt. A variety of 

 Breunnerite, composed of one atom of each 

 of the carbonates of magnesia and iron. 

 S.G. 3-415. 



€omp. Mg C + Fe C. 



Analysis, by Fritzsche : 

 Carbonate of magnesia 

 Carbonate of iron 



. 44-96 

 . 55-27 



100-23 



Locality/. Thurnberg, near Flachau in 

 Salzburg. 



Pitch Coal, Jameson. A name for Jet, 

 having reference to its pitch-like aspect. 



Pitch Opal. An inferior variety of 

 Common Opal. 



Pitchblende, Phillips. Pitch Ore, 

 Jameson. Amorphous: generally occurs 

 massive and disseminated, also botryoidal 

 and reniform, with a columnar or curved 

 lamellar structure. Colour greyish-, green- 

 ish- or brownish-black. Opaque. Lustre 

 dull or submetallic. Streak greenish-black. 

 Very brittle. Fracture uneven or small- 

 conchoidal. H. 5-5. S.G. 6-468 to 8. 



Comp. Proto-peroxide of uranium, or 



TO = uranium 84-78, oxygen 15-22 = 100. 

 Analysis, from the Tanne Mine, Joachims- 



thal, by Rammelsberg : 



Proto-peroxide of uranium . 79-30 



Silica 5 30 



Protoxide of iron . . . 3'03 



Lime 2-81 



Magnesia . . . .0-46 



Lead 6-20 



Arsenic .... 1-13 

 Bismuth, with lead and cop- 

 per 0-65 



Water 0-36 



99-09 

 BB alone, infusible : with borax and salt 

 of phosphorus forms a yellow glass in the 

 outer flame; a green glass in the inner 

 flame. 



Easily soluble in warm nitric and nitro- 

 muriatic acid. 



Localities. — English. Cornwall: St. Aus- 

 tell Consols ; Huel Basset and Huel Buller ; 

 Ting Tang Mine; Tolcarne; Tin Croft 

 Mine, in reniform masses; Huel Trenwith; 

 Huel Providence. — Foreign. Kongsberg, in 

 Norway. Marienberg, Schneeberg, Johann- 

 georgenstadt, and Wiesenthal, in Saxony, in 



PITTICITE. 



botryoidal masses accompanying various 

 ores of silver and lead. Joachimsthal and 

 Przibram, in Bohemia. Retzbanya, in Hun- 

 gary. Adrianople, in Turkey. 



Pitchblende is distinguished from brown 

 Blende by colour, specific gravity, fracture 

 and streak ; from Wolfram, by streak and 

 fracture. Oxide of Uranium (prepared 

 from an acid solution of Pitchblende) is 

 used under the name of Uranium yellow, 

 for colouring glass, to which it imparts a 

 pale opalescent sea-green colour, much ad- 

 mired in Turkey, and used by the Turks 

 and Egyptians for mouth-pieces to pipes. 

 It is also very valuable in porcelain paint- 

 ing, affording an orange tint in the enamel- 

 ling furnace, and a black colour in that in 

 which it is baked. 



Brit. Mus., Case 17. 



31. P. G. Principal Floor, Wall-cases 13 

 (British), 20 (Foreign). 



PiTCHSTONB. A form of Obsidian or 

 volcanic glass, having the lustre of pitch 

 rather than glass. It presents various tints 

 of yellow, green, grey, red, brown and black, 

 and has a resinous lustre inclining to vi- 

 treous. Feebly translucent to opaque. Frac- 

 ture conchoidal, splintery-uneven. H. 5 to 6. 

 S.G. 2-2 to 2-3. 



BB fuses with intumescence, and forms 

 a blebby glass. 



Localities. — Scotch. Arran, Rum, Canna, 

 Mull, Lamlach. Argyleshire. Skuir of Eigg, 

 Hebrides, — Irish. Newry. — Foreign. Si- 

 beria. Iceland. Auvergne. Saxony. Mexico. 

 Peru, &c. 



3LP. G. Upper Gallery, Wall- case 1, 

 Nos. 10, 11, 144. Wall-case 2, Nos. 27, 28. 



PiTCHSTONE OF MeNIL-MONTANT. A 



name given to the darker varieties of Me- 

 nilite, on account of their resemblance to 

 pitch. 



Pitchy Iron Ore, Phillips. A name 

 for Pitticite^ from its more or less perfect 

 resemblance to pitch. 



Pitchy Iron Ore, Jameson. See Trip- 

 lite. 



PiTTiciTE, Beudant. See Vitriol Ochre. 



Pitticite, Hausmann. Pittizite, Levy. 

 Occurs in small masses, reniform and sta- 

 lactitic, resembling pitch in appearance. 

 Colour j^ellowish, reddish, or blackish - 

 brown. Translucent at the edges. Lustre 

 vitreous. Streak pale yellow. Yields to the 

 knife. Brittle. Fracture flat -conchoidal. 

 H. 2 to 3. S.G. 2-3 to 2-4. 



Comp. Arsenio-sulphate of peroxide of 



iron. Pe2 S3 + 2Fe As -!- 24H. (Rammels> 

 berg). 



