246 Di' J. Reinhard Blum on Pseudomorphoua Minerals. 



morphs, and inclines to the opinion on the contrary that the 

 quartz afforded the silica that has altered the bitter spar. 

 Several instances are refeiTed to of massive and columnar 

 quartz in the same region altered to steatite, and also foliated 

 quartz interlaminated with steatite in consequence of a par- 

 tial change. The striae of the surface, still retained, shew 

 that the whole was originally quartz. 



At Gopfersgriin the gangue is a steatitic slate, lying be- 

 tween mica-slate below, and probably granular limestone or 

 dolomite above ; and there is every reason to believe that the 

 steatitic rock is an altered mica-slate. After passing through 

 twenty-four to thirty feet of the decomposed slate of the sur- 

 face, the steatite first appears, and continues for fifty or sixty 

 feet ; below this the pseudomorphous quartz and bitter spar 

 are obtained both in crystals and massive. Near by this the 

 mica-slate becomes penetrated with granular limestone. At 

 Hohlenbrunn the same granular limestone contains, besides 

 masses of quartz, octahedrons of fluor-spar. These facts are 

 urged by Dr Blum as evidence that the same process which 

 produced the steatitic pseudomorphs changed the rock con- 

 taining them from a mica-slate. The steatite replacing the 

 quartz is quite pure ; while that of the slate is brown and im- 

 pure, from the iron in the mica, and looks like a clay-slate. 



The serpentine of Monte Rosa affbrds similar pseudomorphs. 

 Dr Blum describes a geode in his collection, in which the 

 terminal angles are steatite, and the exterior of the crystals 

 has become yellowish-white, or brownish-red, without affect- 

 ing the sharpness of the edges or smoothness of the surfaces. 

 The specimen is from Olmutschen, in Mahren. 



Similar crystals have been found by Professor Emmons in 

 the serpentine of Middlefield, Mass., and by Dr Fowler, in 

 the granular limestone of Newton, N. J. 



Pimelite is supposed by Dr Blum to have often originated 

 by similar changes ; and also Meerschaum at Hrubschnitz, 

 in serpentine, have often, he states, a nucleus of Jirestone, 

 (a coarse kind of opal occurring there in similarly shaped 

 nodules), while others are wholly Meerschaum. Dr Blum 

 suggests, that the silica that has passed off in the change is 



