PENNITE. 



the extremities, and often tabular. Colour 

 bluish,and bluish-greeu b}' reflected light ; by 

 transmitted light, emerald-green in the direc- 

 tion of the axis, and brown at right angles to 

 it. Transparent to translucent. S.G. 2-67. 



Comp. 5(Mg2, Fe) Si + Al Si + 7H. 



Analysis, from Monte Rosa, by Schweizer : 



Silica 33-07 



Alumina .... 9"69 

 Magnesia .... 32"34 

 Protoxide of iron . •. . 11*36 

 Water 12-58 



99-04 



BB swells up and fuses at the edges to a 

 yellowish-white enamel. 



Dissolves in muriatic acid, with separa- 

 tion of silica in a flocculent state, and with 

 still greater facility in sulphuric acid. 



Localities. Ala, in Piedmont. Zermatt, 

 inValais. The Tyrol. 



Name. After the Pennine Alps. 



Brit. Mus., Case 32. 



31. P. G. Horse-shoe Case, No. 1170. 



Pennite, Hermann. Occurs in whitish 

 or pale green incrustations, having a sur- 

 face of minute spherules. Lustre weak. H. 3. 

 S.G. 2-86. 



Comp. CaC + 2MgC + H. 



Analysis, from Texas, by Hermann : 

 Carbonic acid . . . 44-54 

 Magnesia .... 27*02 



Lime 20-10 



Oxide of nickel . . . 1-25 

 Protoxide of iron „ . . 0-70 

 Protoxide of manganese . 0-40 

 Alumina .... 0-15 

 Water 5-84 



PEPJCLASE. 



Magnesia 



Lime .... 

 Protoxide of manganese 

 Water .... 



277 



. 7-99 

 . 0-50 

 . trace 

 . 8-30 



100-00 

 BB alone, infusible. 



Localities. — British. The Shetlands : 

 Swinaness, on chromate of iron with Eme- 

 rald Nickel; Haroldswick, in Unst, mas- 

 sive-foliated. — Foreign. Texas, Lancaster 

 CO., Pennsylvania, U.S. 



Pentaklasit, Hausmann. See Pyr- 

 oxene. 



Pentlandite. a variety of Eisen-nic- 

 kelkies, from Craignure. 



Name. After J. B. Pentland. 

 Peplolite. a pseudomorph, after lolite, 

 from Ramsberg, in Sweden. H. 3 to 3-5. 

 S.G. 2-68 to 2-75. 



Analysis, (mean of three) : 



Silica ..... 45-95 

 Alumina .... 30-51 

 Protoxide of iron . . . 6-77 



100-02 

 Name. From jtsVao?, a cover, and xiQo(, 

 stone. 



Peponite. Dufrenoy, A variety of 

 fibrous, acicular and radiated Tremolite, 

 forming kidneys in a serpentinous rockj 

 mixed with oxydulated iron, at Berggies- 

 Shiibel in Saxony. It has a more decidecl 

 green tint than Calamite, the result, doubt- 

 less, of its association with Serpentine ; and 

 its lustre is, also, very slight. 



Percylite, H. J. Brooke. A Chloride 

 (perhaps oxychloride) of lead and copper. 

 Occurs in minute cubes. Colour and streak 

 sky-blue. Lustre vitreous. H. 2-5. 



Comp. (Pb,Cl + Pb) + (Cu,Cl + Cu)-i-H. 



BB fuses readily; on charcoal, in the 

 inner flame, affords metallic globules, which 

 dissolve without residue in dilute nitric 

 acid. 



Locality. La Sonora, in Mexico, accom- 

 panying Gold, in a matrix of Quartz and 

 Red Oxide of Iron. 



Name. After John Percy, M.D., Pro- 

 fessor of Metallurgical Chemistry in the 

 Government School of Mines, 



Brit. Mus., Case 57 B. 



Periclase ; Periclasia, Scacchi. Peri- 

 KLASE. Cubical. Occurs in octahedrons, 

 with a perfect cubic cleavage, and in grains. 

 Colour dark-green. Lustre vitreous. Trans- 

 parent to translucent. H. 6. S.G. 3 •75. 



Comp. Mg, or magnesia with 5 to 8 per 

 cent, of protoxide of iron. 

 Analysis, by Damour : 



Magnesia . , . . 93-86 

 Protoxide of iron . . .5-97 



99-83 



BB infusible. 



Slowly soluble in nitric acid when re- 

 duced to powder. 



Locality. Monte Somma, in ejected masses 

 of white limestone. 



Name. From s-e?/, around, and xXxm, cleav- 

 age, in allusion to the cleavages at the 

 angles. 



Periclase is most surely distinguished by 

 cubical cleavage from the white Peridot- 

 olivine with which it is associated. It is 

 distinguished from Fluor and Scheelite 

 (Tungsten), which it resembles in external 

 characters, by cleavage and hardness. 

 t8 



