Scientific Intelligence — Mineralogy. 189 



labour, during which his wheel was much injured, he did not suc- 

 ceed in grinding a single one of the angles presented by the surface. 

 Dumas expressed the opinion, that it may be a so-called diamant 

 de nature, by which is meant one of the dull diamonds, exhibiting 

 no cleavage, which, when reduced to powder, are employed in cutting 

 the diamond. These, however, are not black, and it would be an 

 interesting circumstance if the substance in question should prove to 

 be a diamond, which has retained the opacity and black colour of 

 coal. — Berzelius^ Jahres-Bericht, 24.th year, p. 295. 



13. Formation of Iron-Glance hy sublimation. — ^Mitscherlich's 

 theory of the formation of iron-glance in the fissures and clefts of 

 volcanic mountain-rocks, by the aid of chlorine, is well supported by 

 a phenomenon which has taken place in the salt-mines of Wieliczka. 

 It has sometimes happened that the extensive wood-work of these 

 vast mines has been destroyed by fire ; and the iron-work and im- 

 plements have at the same time suffered. Von Hrdina, one of the 

 officers of the mines, shewed me specimens of saliferous clay, ob- 

 tained from the vicinity of such conflagrations, in which the fissures 

 were lined and impregnated with iron-glance. A recent formation 

 of iron-glance has thus evidently taken place, in which chlorine must 

 have performed a part. — Professor Ndggerath, in Karsten's Archiv, 

 vol. xviii., p. 538. 



14. Greenovite proved to be a variety ofSphene. — In vol. xxxiv. 

 p. 183. of this Journal, we noticed the substance termed Greeno- 

 vite by M. Dufrenoy. Subsequently, Breithaupt expressed an opi- 

 nion, founded on external characters, that this mineral was a sphene 

 in which the lime was replaced by the protoxide of manganese. In 

 No. 106 of the Bibliotheque Universelle de Geneve, we find two 

 papers on Greenovite, the one by M. Achille Delesse, and the other 

 by Professor Marignac ; and both authors regard this substance as 

 identical with sphene. M. Delesse mentions, that he received a 

 specimen from M. Dufrenoy, which enabled him to make a more 

 satisfactory analysis than it had been possible for M. Cacarrie to 

 perform at first with the small quantity at that time obtained. The 

 specific gravity, as determined by M. Delesse, is 3-483, a number 

 intermediate between that given by M. Dufrenoy, viz. 3-44, and that 

 given by Breithaupt, viz. 3-527. After carefully separating the 

 veins of quartz which traverse the crystals of Greenovite, and are also 

 interposed between the cleavage faces ; and after employing all other 

 possible precautions, M. Delesse obtained the following results from 



two analyses : — 



I. Oxygen. II. Oxygen. 



Silica, .... 0-298 0-1548 0-304 0-1579 



Oxide of Titanium, . . 430 0-1707 0.420 0-1668 



Protoxide of Manganese, 0-029 ) 0-038j 



Protoxide of Iron, . . trace } 0.0728 trace ^ 0-0<68 



Lime 0-236 1 0-243) 



0-993 1*005 



