PUFFLERITE. 



botrvoidal, and stalactitic. Colour iron- 

 black, passing into dark steel-grey. Opaque. 

 Lustre submetallic. Streak brownish- black 

 and shining. Brittle. Fracture flat-con- 

 choidal. H. 5 to 6. S.G. 4-08 to 4'36. 



Comp. Mn5ifn2 + H mixed with Mn, 

 part of which may be an accidental admix- 

 ture. The Mn is often partly replaced by 



K, Ba, Ca, Cu, &c. 



Analysis, from Romaneche, by Turner : 

 Proto-peroxide of manganese 70-97 

 Oxygen .... 7-26 



Bafyta 16-69 



Silica 0-95 



Water 4-13 



100-00 



BB gives a violet colour to borax. 



Soluble in muriatic acid (except a small 

 quantity of silica), with evolution of chlo- 

 rine. 



Localities. — English. Eestormel Royal 

 Iron-mine, Cornwall, in fine velvet-black 

 stalactitic masses. Devonshire : Upton Pyne, 

 near Exeter ; near Bideford ; Black Down, 

 near Tavistock; botryoidal and stalactitic. 

 Ash ton, near Chudleigh. Brendon Hill JVIine, 

 Somersetshire. Dry gill, in Cumberland 

 Hartshill, in AVarwickshire. — Scotch. Lead- 

 hills. Old Kilpatrick, Dumbartonshire. 

 Orkneys; in old red sandstone at Brae- 

 borough (coralloidal). — Irish. Glendore, co. 

 Cork. — Foreign. Ihlefeld, in the Harz. 

 Siegen, in Hesse. limenau. Schneeberg. 

 Horhausen. Heidelberg. Romaneche. Haute 

 Saone. Vermont, United States. 



Name. From 4'^*?, smooth, and f^i^'^;, 

 black : in allusion to its smooth or botryoidal 

 form and black colour. 



Brit. Mus., Case 13. 



M.P.G. Principal Floor, Wall-case 13 

 (British). 



This is a common ore of Manganese, and 

 is frequently associated with Pyrolusite, 

 with which it sometimes forms alternatnig 

 layers of varying thickness. The beautiful 

 dendritic or moss-like delineations often met 

 with in the crevices of rocks are frequently 

 produced by the infiltration of Psilomelane. 



PuFFLERiTE, Dufrenoy. The name given 

 to the globular Prehnite of the Seisseralp in 

 the Tyrol, where it occurs in the form of 

 kernels in amygdaloidal trap, associated 

 •with Chabasie. 



Pumice, Pumite {French'). Vesicular or 

 porous, so as to swim in water. Colours pale 

 yellowish-grey, passing into grey, brown. 



PYCNITE. 80S 



and black. Very brittle. Fracture uneven 

 and conchoidal. "H. 5. S.G. 2-2 to 2-4. 

 Analysis, from Lipari, by Kluproth ; 



Silica 77-50 



Alumina .... 17-50 

 Peroxide of iron . . .1-75 

 Water 3-00 



99-75 



BB fuses to a whitish glass, 



Localities. Lipari Islands. Htingary. 

 Banks of the Rhine, between Andernach and 

 Coblentz. The summit of Puy Clerzoux, 

 in Auvergne. Iceland. Island of Santorin, 

 in the Grecian Archipelago. Ponza Islands. 

 Ascension. Tenerifie. Aden. Ischia. 



Pumice is a porous felspathic scoria, thrown 

 out by volcanoes during the periodical explo- 

 sions which take place simultaneously Avith 

 their more quiet action, when ashes, cinders, 

 masses of rock, and melted lava are hurled 

 into the air by the action of pent-up steam 

 and gases. Pumice, one of the ejected sub- 

 stances in question, becoming cooled in its 

 passage through the air, retains the porous 

 spongy structure it originally possessed, ow- 

 ing to the presence of the vapours or gases 

 with which it was permeated at the time it 

 was shot forth in a melted state. 



Pumice is used at Andernach as a build- 

 ing stone. — It is also employed for polishing 

 stones, metal, glass, and ivory; also, in a 

 powdered state (under the name of pounce), 

 for preparing parchment. 



J£ P. G. Unper Gallerv, Wall-case 1, 

 iN'os. 14 to 16, 143 ; Wall-case 2, Xo. 63. 



PuEPLE Copper, Kirwan, Phillips. See 

 Erubescite. 



PuscHKiNiTE, Wagner. A green, yellow, 

 or red variety of Epidote, from Werchne- 

 udinsk and Katherinenburg, in the Ural, 

 Avith a composition similar to that of the 



Pistacite of Burawa, or 2(R Si + ft Si) -f 



(2RSi + 3itSi). S.G. 3-066. 



Pycnite, Haiiy. A massive variety of 

 Topaz, with a parallel columnar structure, 

 and oblique transverse divisions, along 

 Avhich it may be easily broken. Colour dull 

 yellowish- or reddish-white. Translucent. 

 Lustre vitreous. Brittle. Fracture imper- 

 fect-conchoidaL H. 7-5. S.G. 3-51. 



Comp. Al Si, with 1th of the oxygen re- 

 placed by fluorine. 



Analysis, from Altenberg, by Berzelius : 

 Alumina . . . .51-00 

 Silica 38-43 



