308 Mr Haidinger's Description of' Pyrolusite. 



berg. They are imbedded in small veins of quartz and calca- 

 reous spar in clay-slate, particularly where they cross each 

 other. Distinct though small crystals are met with in many 

 of the mines in the west of Germany, for instance at Tiefe 

 Kohlenbach in Siegen ; still smaller ones were found many 

 years ago in the Palffy iron-mines of Haerethof near Frohstorf 

 in Austria, associated with gray quartz. Very small crystals 

 are found imbedded in and alternating with layers of black 

 wad in Bavreuth. A variety much resembling the German 

 ones, found in similiar repositories, occurs at the mine of An- 

 tonio Pereira near Villa Ricca in Brazil, along with brown he- 

 matite and psilomelane, in beds in clay-slate, produced accord- 

 ing to Dr PohPs account, from the decomposition of sparry 

 iron. 



Small granular pyrolusite occurs at Skidberget in the parish 

 of Lepand in Dalecarlia, Sweden. But the individuals are 

 often much smaller, and appear in the form of a black sooty 

 substance. Such are frequently found in the iron mines of 

 Raschau and other places in Saxony, also at Platten and other 

 similar repositories in the north of Bohemia ; sometimes they 

 include small globules and reniform masses of red hematite, or 

 red iron-ochre. The same pulverulent oxide occurs also at 

 Schladming in Stiria, at Felsobanya in Hungary, and at Put- 

 ten in Austria. Dr Pohl observed several localities of it in 

 Brazil, as at St Toao d'el Rey, with brown hematite ; on the 

 road between Anta and S ta Rita, in the capitania of Goyaz, 

 and at Banedrinha do Caelho in Minas Geraes. In the latter 

 place it includes numerous reddish nodules, or cylindrical and 

 ramified concretions of indurated clay. 



The pyrolusite, as was observed above, is very generally 

 found along with psilomelane. In fact, it is seldom found 

 without it. Another species frequently accompanying it is 

 the brown hematite, and these two species, like the pyrolusite 

 and psilomelane, are often very curiously associated with each 

 other. At Arzberg in Bayreuth crystals of quartz are found 

 covered with a stratum of brown hematite, upon which is de- 

 posited another distinct stratum of pyrolusite. In some va- 

 rieties from Berge in the county of Salm, thin stalactites of 



