Scientific Intelligence — Mineralogy . 197 



The Tliomiiite approaches pretty nearly the Junkerite, and the 

 crystallographic form is the same ; but the great distinction between 

 the two minerals consists in the very peculiar crystalline-granular 

 constitution of the ThomJiite ; besides the difference in specific gra- 

 vity, fracture, colour, &c. — [Lconhard^s Jahrbuch, 1845, Heft 2, 

 p. 200.) 



25. Analysis of Tscheiuklnite. — ^We formerly published an account 

 of this remarkable mineral in vol. xxix., p. 418, of this Journal. The 

 Tschewkinite was first made known by Gustav Rose ; and Henry 

 Rose has lately published, in PoggendorfF's Annals (vol. Ixii., p. 592) 

 the following more complete analysis, which is the mean of not less 

 than six distinct analyses : — 



104-38 



The excess in the analysis arises from the oxide of cerium exist- 

 ing in the mineral in the form of protoxide. Complicated as the 

 composition of Tschewkinite is according to the above analysis, there 

 still appear to be minute portions of other constituents ; for Profes- 

 sor Henry Rose detected a slight trace of yttria, and what seemed 

 to him slight ti'aces of glucina and alumina. 



20. Vanadium- Bronzite. — Schafhiiutl has described and analysed 

 a bronzite containing vanadium, from the steatitic rocks of Bi'acco, on 

 the Genoese coast. It is large-foliated, with one distinct and two 

 indistinct cleavages ; has a pearly lustre, is translucent in thin frag- 

 ments, is of a greenish-grey colour, scarcely so hard as fluor-spar, 

 and easily frangible. Specific gravity = 3-255. Its composition 

 is nearly the same as that of the bronzite of Salzburg, except that 

 a portion of the oxide of iron of the latter is replaced by oxide of 

 Vanadium and soda. — (L' Institut, No. 589.) 



27. Variety of Xantholeone resembling Grccnockitc. — Breithaupt 

 formerly dusciibed in Eidniaun's Journal ('vol. xx., p. 67) a mineral 

 which had been found, in the year 1797, in the celebrated mine of 

 Himmelsfiirst, at iiibisdurf, near Freiberg, and which he named 

 xanthokonc, on account of its yellow streak. Dui'ing a visit to the 

 same mine in October 18-44, Breithaupt found crystals of this mine- 

 ral imbedded in calcareous spar, and presenting a great resemblance 

 to Greonockite. Tlie crystals are very thin hexagonal tables ; the 



