282 PHENACITE. 



Localities. — English. Cornwall, Jigs. 327, 

 328, in tetrahedral crystals at Hue'l Jane ; 

 Huel Gorland; Huel Unity; Carharrack 

 Mine; CarnBrea; Botallack. In cubes at 

 Burdle Gill in Cumberland, on Quartz. — 

 Foreign. St. Leonard in France. Schnee- 

 berg and Schwartzenberg in Saxony. Aus- 

 tralia. 



Name. From <px^/u,(x,y,ov, poison, and a-ihij^os, 

 iron. 



Brit. Mus., Case 56. 



Phenacite, Dana. Phenakite, Nor- 

 ■denskiold. Hexagonal, often hemihedral. 

 Primary form a rhombohedron. Colourless 

 or bright wine-yellow, inclining to red. 

 Lustre vitreous. Transparent to opaque. 

 Eefracts doubly. Fracture conclioidal, like 

 that of Quartz. H.7-5. S.G.2-966 to 2-99. 



Fig. 329. 



^C^^ 



VV 



Fig. 330, 



Comp. Silicate of gluoina, or Bel5i = 

 silica 55, glucina 45 = 100. 



Analysis, from Perm, by Hartwall : 



Silica 55-44 



Glucina .... 44-47 

 Magnesia and peroxide of 

 iron traces 



99-61 



BB alone infusible: with borax slowly 

 forms a clear glass ; with carbonate of soda 

 aflFords a Avhite enamel. Ignited with solu- 

 tion of cobalt assumes a dull bluish colour. 



Localities. Siberia : in mica-slate at the 

 emerald- and chrysoberj'l-mine of Ka- 

 tharinenburg, in crystals sometimes nearly 

 four inches across ; in small crystals, on the 

 east side of the Ilmen mountains, north of 

 Miask, with Topaz, &c. In brown Iron Ore 

 at Framont in Alsace. Durango in Mexico. 



Name. From (pival, a deceiver; from its 

 resemblance to Quartz, for which it may be 

 mistaken. 



Brit. Mus., Case 26. 



Phengite, v. Kobell. See Muscovite. 



Phillipsite, Beudant, Dufrenoy. Purple 

 Copper. See Erubescite. 



Phillipsite, Levy. Rhombic : primary 

 form a right rectangular prism. Occurs in 

 tAvin or compound crystals resembling those 

 of Harmotome. Colour white, inclining to 

 grey and sometimes pink. Lustre vitreous. 



PHLOGOLITE. 

 Translucent to opaque. Streak white. 

 Brittle. Fracture uneven, conchoidal. 

 H. 4-5. S.G. 216 to 2-21. 



Fig. 331. 



Comp. K Si + 2Ca Si + 4A1 Si^ + 18H. 



Analysis, from Marburg, by L. Gmelin : 



Silica 48-51 



Alumina .... 21*76 

 Peroxide of iron . . . 0-99 



Potash 6-33 



Lime 6-26 



Water 17-23 



101-08 



BB gives off water, swells slightly, and 

 fuses to a translucent glass. 



Readily and completely decomposed by 

 muriatic acid, with the formation of a jelly 

 of silica. 



Localities^ — Irish. Plaiskins, a headland 

 near the Gianfs Causeway, in white trans- 

 lucent crystals, in cellular trap rock,^^. 331. 

 Magee Island, Londonderry, in minute flesh- 

 coloured crystals in amygdaloid. — Foreign. 

 Capo di Bove, near Rome, in groups or 

 sheaf-like aggregations. Aci Reale. Among 

 the lavas of Vesuvius. Stempel near Mar- 

 burg. Cassel. Giessen. Saint-Pancrace, 

 Dept. de I'Aude, in France. Iceland. 



Name. After the late William Phillips, 

 author of " An Elementary Introduction to 

 Mineralogy." 



Brit. Mus., Case 29. 



Phlogolite, or Phlogopite, Breit- 

 haupt. A uniaxial magnesian Mica belong- 

 ing to the Biotite group. Rhombic. Oc- 

 curs in rhombic or hexagonal prisms. 

 Cleavage basal. Colour yellow or copper- 

 red ; also colourless, white or brown. 



Comp. 2A1 si + 3(Mg, K, Na) Si. 



Analysis, from the Vosges, by Delesse : 



Silica 37-54 



Alumina .... 19-80 

 Protoxide of iron . . . 1-61 

 Protoxide of manganese . O'lO 

 Magnesia .... 30-32 

 Potash .... 7-17 



Soda 1-00 



Fluorine . . . .0-22 

 Loss, ignition, &c. . .1-51 



99-97 



