288 PIHLITE. 



incrustation on the sides of certain caves, in 

 the granite cliffs on the coast of Cornwall. 

 It is of a brown colour in mass, and in 

 powder of a yellow colour. Insoluble in 

 water and alcohol. In the air, at a bright 

 red heat, this mass burns very slowly, 

 and leaves a grey or white ash, consisting of 

 alumina with some slight foreign ad- 

 mixtures. 



Comp. 4A1 + C12H5 08 + 27H. 



Name. After the Rev. M. Pigot. 



The organic constituent of Pigotite is 

 considered by James F. Johnston to be de- 

 rived from the decay of the various plants 

 which grow on the nioist moorlands above, 

 and which being carried by the waters into 

 fissures in the granite beneath, combines 

 with the alumina of the decomposed Felspar, 

 and when it reaches the air, deposits itself 

 over the roof and sides of the caverns in the 

 form of layers varying from two to three 

 inches in thickness. 



Brit. Mus., Case 60. 



PiHLixE, Seftstrom. A doubtful mineral 

 species between Talc and Mica, from Fah- 

 lun in Sweden. Colour green. Lustre dull. 

 Structure lamellar. 



PiKROSMiN, Haidinger. 



PiMBLiTE, Karsten. Massive or earthy. 

 Colour apple-green or yellowish green. 

 Translucent, with a dull greasy lustre. 

 Feels greasy. Does not adhere to the 

 tongue. Streak greenish-white. H. 2*5. 

 S.G. 2-23 to 2-3. 



Comp. (Ni, Mg3)Si + 24feSi 



+ 9H. 



Analysis, by Baer .• 





Silica .... 



. 35-80 



Alumina 



. 23-04 



Peroxide of iron . 



. 2-69 



Oxide of nickel . 



. 2-78 



Magnesia 



. 14-66 



Water . . « , 



. 31-03 



100-00 



BB fuses to a slag only at thin edges : 

 with borax gives a reaction of nickel. 



Locality. Frankenstein, &c., in Silesia. 



Name. From miu.iXvi, fat, and x<U?, stone. 



Brit. Mus., Case 25. 



PiNGUiTE, Berthier, Breithaupt. A va- 

 riety of Chloropal, resembling Bole. Oc- 

 curs in masses of a siskin- or dark oil- 

 green colour. Opaque or semitranslucent. 

 Lustre slightly resinous. Streak paler than 

 the colour. Feels greasy. Does not ^ ad- 

 here to the tongue. Gives off a slight 

 argillaceous odour when struck. Very 

 soft, like newly made soap; does not be- 



PINITE. 



come softer by immersion in water. Very 

 sectile. Fracture flat-conchoidal or uneven- 

 splintery. PL 1. S.G. 2-315. 



Comp. Fe Si + Fe2 si^ + 15H. 

 Analysis, from Wolkenstein, by Kersten : 

 Silica 36-90 



Alumina 



. 1-80 



Peroxide of manganese 



. 0-15 



Peroxide of iron . 



. 29-50 



Protoxide of iron 



. 6-10 



Magnesia 



, 0-45 



Water .... 



. 25-10 



100-00 



BB becomes black, and fuses at the edges 

 only; with carbonate of soda fuses to a 

 black slag ; dissolves in borax, exhibiting 

 the reaction of iron. 



Readilj^ decomposed by warm muriatic 

 acid, with separation of pulverulent silica, 

 which retains the greenish colour of the 

 mineral till it has been digested a consider- 

 able time. 



Localities. Wolkenstein and Geilsdorf, in 

 Saxony, in veins of Heavy Spar in gneiss, 

 Tannhof, near Zwickau. Suhl, in the Thll- 

 ringer Wald. 



Name. From pinguis, fat, or grease, 



Brit. Mus., Case 26. 



Finite, Werner. Finite, Haily. An 

 alkaline variety of altered lolite. Occurs in 

 six-sided or twelve-sided prisms, of which 

 the lateral, and sometimes the terminal, 

 edges are replaced. Cleavage sometimes 

 basal, but often indistinct. Colour dirty 

 grey, greyish-green, or brown. Slightly 

 translucent or opaque. Lustre feeble. Yields 

 easily to the knife. Streak white. Fracture 

 uneven and splintery. H, 2-5. S.G. 2-78. 



Fig. 335. 



Analysis, from Auvergne, by C. Gmelin . 



Silica . 



. . 55-96 



Alumina 



. 25-48 



Protoxide of iron . 



. 5-51 



Magnesia 



. 3-76 



Potash . 



. 7-89 



Soda . 



. 0-39 



Water . 



. 1-41 



100-40 

 BB becomes colourless, and fuses at the 

 edges to a blistered glass, which is either 



