306 PYEITE DE BOOM. 



Cumberland. Sussex : on the range of 

 Downs between Sullington and Amberley 

 Mount, in Upper Chalk. — IVelsh. Pary's 

 Mine, Anglesea. — Scotch. Leafihills, La- 

 narkshire. Perthshire. — Irish. Prehen and 

 Hollywell Hill, near Derry, in hornblende- 

 slate. Ballygahan and neighbouring mines, 

 Wicklow. — Foreign. Elba, in pentagonal 

 dodecahedrons, &c. Traversella, in Pied- 

 mont. Persberg and Fahlun, in Sweden, 

 Kongsberg, in Norway. Milnden, in Hano- 

 ver. Peru. Huelva mines in Spain, con- 

 taining from 1 to 10 per cent, of copper 

 (on an average 3 to 4 per cent.). 



Name. From frv^lrr,?, full of fire ; in allu- 

 sion to its striking fire with steel. See 

 Pierre d'Arquebuse. 



Brit. Mus., Case 6. 



3I.P.G. Principal Floor, Wall-case 36, 

 J^os. 95, 35, and 46 (British) ; 19 (Foreign). 

 Horse-shoe Case, Nos. 149 to 154. 



The greater part of the copperas and sul- 

 phuric acid of commerce is manufactured 

 from Iron Pyrites, as well as much of the 

 sulphur and alum. 



The term Pyrites was restricted to nodules 

 of sulpliide of iron by Dr. Woodward and 

 pome of the older mineralogists ; the word 

 Marcasite being applied by them to veins or 

 perpendicular iissures of Iron Pyrites. 



Pyritk de Boom. Speerkies, or Mar- 

 casite, from the tertiary clays of Boom, on 

 the river Kappel in Belgium. It is used 

 instead of sulphu.r in the manufactory at 

 Brussels, for making sulphuric acid. 



Pyritb Cuivreuse, Brochant. See 

 Chalcopyrite. 



Pyrite d'Etain, Brochant. See Tin 

 Pyrites. 



Fyrite Magnetique, Brochant. See 

 Pyrriiotine. 



Pyrite Martiale, Brochant. See 

 Pyrites. 



Py'ritous Copper. See Chalcopyrite. 



Pyrochlore, W'uhler. Cubical. Occurs 

 in regular octahedrons, with indistinct octa- 

 hedral cleavage. Colour pale honey-yellow, 

 reddish- or blackish-brown. Opaque or 

 translucent at the edges, exhibiting a 

 brown colour by transmitted light. Lustre 

 vitreous or resinous. Streak light-brown to 



Fig. 350. 



vellow. Brittle. Fracture conchoidal. H. 5 

 to 5-5. S.G. 4-206 to 4-326. 



PYROELECTRIC WAVELLITE. 

 Comp. About 4(Ca, Mg, Ce, La, Y, U) Ti 



Ta (Z/. Gmelin). 



Analysis, from Miask, by Hermann 



Coiumbic acid 



. 62-25 



Titanic acid . 



. 2-23 



Zirconia 



. 5-57 



Protoxide of iron . 



. 5-il 



Lime .... 



. 13-54 



Yttria . 



. 3-09 



Protoxide of lanthanum 



. 20-00 



Potash, soda, and lithia 



. 3-72 



Protoxide of manganese 



. trace 



Fluorine 



. 3-00 



101-71 



BB becomes of a pale brownish-yellow 

 colour, and fuses with great difficulty, yield- 

 ing a black slag. With borax, in the inner 

 flame, forms a clear reddish-yellow glass. 



Decomposed by long digestion with oil of 

 vitriol at high temperatures. 



Localities. Norway : Frederiksvarn and 

 Laurvig, in syenite, and associated, with 

 Zircon, Polymignite, &c. ; Brevig, with 

 Thorite. Ilmengebirge, near Miask, in 

 Siberia. 



Name. From sriJg, fire, and x^^^i^?, green ; 

 in allusion to its forming a glass with mi- 

 crocosmic salt, which, in the outer flame, is 

 yellow while hot, but becomes grass-green 

 on cooling. 



Brit. Mus., Case 37. 



Pyrodmalit, Leonhard, \ See ' Pyro- 



Pyrodmalite, Beudant,} smalite. 



From T!^?, fire, o^f^'h, odonr, and A/^o?, stone ; 

 from the odour it gives off when heated. 



Pyroeeectrio Wavellite. Occurs in 

 small emerald-green crystals mingled Avith 

 Avhite crystals, forming mammillated con- 

 cretions cementing fragments of a quartzose 

 grit, or forming the cement of a conglomer- 

 ate composed of a black chertlike variety of 

 Jasper. 



Comp. 5(A1 Pe) 3P + 18H. 

 Analysis, by Alphonse Gages . 



Alumina 



Silica . 



Phosphoric acid 



Peroxide of iron 



Phosphate of lime 



Iron 



Quartz 



Oxide of nickel 



Water . 



36-16 

 3-61 



30-88 

 1-81 

 1-58 



trace 

 1-00 

 0-32 



23-56 



Locality. 



98-92 

 Found by Messrs. Jukes and 



