Mineralogical Notices from Foreign Journals. 121 



Its constitution may be expressed by the formula 



^/}si^+MgH. 



which at the same time indicates its near reh^tion to ser- 

 pentine. 



PENNINE. BY PROF. J. FROBEL AND M. SCHWEIZER. 

 [From Poggendorff's Annalen, vol. 1. Part 3.] 

 Under this name (derived from the Pennine Alps, in which 

 district, near Zermatt, it occurs) Prof. J. Frobel has described 

 a mineral bearing great resemblance to the chlorite from Ach- 

 matowsk and the Zillerthal. Hexagonal, with very distinct 

 basal structure. The well-developed crystals generally present 

 at times the tabular, at times the columnar combination of the 

 faces of a rhombohedron with the horizontal pair of faces, 

 as shown in the annexed wood-cut. 



The values P on Ro = 99°, of 

 Ro on Ru = 118°. Hardness on ^^^-"""v ^ '~^^'~Z^^ 



the basal faces somewhat above \j rV^o 



that of gypsum, on the rhombo- ^^ .^--y ~*-'^""""~"~\--._ 



hedral faces not quite equal to "~~--^-Z \-^ 



that of calcspar. Thin leaves 



flexible, but not elastic. By reflected light, black-green; 

 by transmitted light, in the direction of the principal axis be- 

 tween emerald-green and leek-green, at right angles to the 

 principal axis brown to hyacinth-red. Lustre vitreous ; when 

 not too thick, perfectly transparent. The results of two analyses 

 by M. Schweizer gave 



SiUca 33-82 33-07 



Protoxide of iron Il-SO 11'36 



Alumina 9-32 9*69 



Magnesia 33-04' 32*34< 



Water 11-50 12-58 



98-98 99-04 



leading to the formula 



M""'^ r ■ • 



.« i Si^ + Al Si-' + 7MgH, 



iv L - - _ 



which is constructed according to the same principle em- 

 ployed by M. Varrenlrapp for cldorite. 



CHLOUOSPINELLE AND XANTHOPHYLLITE. BY PROF. G. ROSE. 



[From Poggcnclorfl's ,/»««/<■», vol. 1. Part 4.] 



C/ilorosjnnclle occurs crystallized in octahedrons generally, 



