g4r 0*f SPURIOUS CRYSTALS. 



form of crys- ncHtls, that are commonly amorphous, as the steatite, specie- 

 stein of Werner, ami serpentine. Nature, which very rarely 

 imleed allows the species, of which these arc varieties, to as- 

 sume its proper forms, seems to have designed to indeninify it, 

 by placing it in situations favourable for borrowing those of 

 certain species, which appear to yield them up with more rea- 

 diness, in proportion as they are more susceptible of variation. 



DifForent crys- '^''^* Steatite of Bayreuth, of which there are many speci- 



talline forms mens in the collection of tlie Council of Mines, sent by Dr. 



steatkeofBav- Scheider, a physician at Hoff, in Franconia, exhibits several 



reuih. pseudomorphoses. The chief of these are the primitive rhom- 



boid of carbonate of lime; those of the equiaxaland inverse 

 varieties of the same species, as well as the dodecaedron, with 

 scalene triangular pyramids opposed base to base, the melasta- 

 fiqiie of Haiiy ; the hexagonal prism, terminated at each end 

 by hexaedral pyramids, of the prismatic hyaline quartz, 

 sometimes alternate, at others bisalternate and flattened. 



Steatite from A steatite from Carlsbad in Bohemia has exhibited to JMr. 



Caribbad. Haiiy a remarkable pseudomorphosis, consisting in an oblique 



prism with a rhombic base, similar to the binary feldtspar. It 



^^> forms part of a rock with base of feldtspar, which serves it for 



^^ a gangue. This interesting specimen was sent by prof, J urine 



of Geneva, who has a duplicate of it in his collection. 



Serpentine.' Mr. de Champeaux, to whom we are indebted for a know- 



ledge of the situations, in which uranium, oxide of titanium, 

 emeralds, and graphic granite are found in the department of 

 the Saone and Loire, one of those which that engineer of 

 Mines has the charge of inspecting, has found in the valley of 

 Viege, at Mont-Rose, a serpentine interesting for the novelty 

 of the regular figures it exhibits. This substance, which is 

 in the collection of the Council of Mines, is of a greenish co- 

 lour, a little transparent on the edges, and nearly approaches 

 the noble serpentine of Werner. Oligist iron, or specular iroa 

 ore, is disseminated in it. It exhibits, besides, 1st. the form 

 of the prismatic hyaline quartz, their being no difference that 

 can be appreciated between the inclinations of the faces, and 

 values of the angles, when they are compared together: 2<lly. 

 the same form modified by facets occupying the places of the 

 edges contiguous to the summits of the pyramids, which had 



neycr 



