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Mineralogy and Geology. 1 13 



II. Mineralogy and Geology. 



1. Analysis of Ehlite; by R. Rhodius, (Wohl. and Liebig's Annal., 

 ?xii, 372.) — Ehlite is found by R. Rhodius to consist of oxyd of cop- 

 per 63-1, phosphoric acid 289, water 7*3:=:99-3. It is blackish olive 

 green in color, and has an uneven fracture. Specific gravity 4*27. It 

 occurs at Eld near Linz on the Rhine, associated with quartz and 

 chalcedony. The composition proves its identity with Libethenite as 

 heretofore supposed. 



2. Analysis of Brandisite ; by von Kobell, (Leonhard und Bronn, 

 Neues Jahrbuch, 1848, p. 217.)— Consists of silica 2000, alumina 

 43*22, peroxyd of iron 360, magnesia 25*01, lime 4*00, potash 0*57, 

 water 360, oxyd of copper and manganese, a trace. 



3. On Volknerite, a new Mineral; by M. Hermann, (Erdm. und 

 March. Jour., xl, 12; Leonh. und Bronn, Neues Jahrb., 1847, 848.) 

 Volknerite comes from a talcose slate in the district of Slatoust in Si- 

 beria, and was named in honor of Captain Volkner. It occurs in 6-sided 

 tabular crystals, with a very perfect basal cleavage, white color, pearly 

 luster, greasy feel, with the specific gravity 2'04. In the forceps be- 

 fore the blowpipe it swells up somewhat, but does not melt ; with cobalt 

 it affords a rose-red color. With the fluxes it fuses with efiervesence 

 to a colorless glass. Composition, alumina 17-75, magnesia 38*59, wa- 



ter 43-76 ; giving the formula Mg 6 A1-J-15H. 



4. Ceramohalife ; J. Jurasky, (Ost. Blatter fur Lit., 1847, No 109, 

 P- 434 ; Leonh. und Bronn, Neues Jahrb., 1847, 848.)— Ceramohalite 

 occurs in thick druses with iron-vitriol near Konigsberg in Hungary. 

 » is in 6-sided tables, affording angles according to Haidinger of 

 v* and 134°, and belongs to the monoclinate system. It is very solu- 

 ble, has an acid reaction, and an astringent taste. When heated, it 

 deliquesces, gives out water and becomes finally % porous mass which 

 is easily soluble in heated water, though difficultly so in cold. Com- 

 position, alumina 14*30, protoxyd of iron 2*15, sulphuric acid 36*75, 

 water 44-60, insoluble residue 2-01=99-81, leading to the formula 



• - • 



• » . 



AI S*-f I8H. 



5. Feldspar in the " Orbicular Dior it e" of Corsica; by M. Delesse. 

 *j--lhe orbicular diorite is a granitoid rock consisting of feldspar and 

 hornblende and occurring in concentric aggregations. The feldspar is 

 franslucent and white, with a grayish or bluish shade. Specific grav- 

 u y 2*737. Its crystals are like those of common feldspar or albite; 

 yet is generally in thin crystalline lamina?. It is easily attacked by 

 hydrochloric acid, which decomposes it completely, the silica separating 

 as a powder. Composition, according to the analysis of Delesse, silica 

 48< 62, alumina 34*66, protoxyd of iron 0*66, lime 12*02, magnesia 

 °'33, soda 2*55, potassa 1*06, water 049=: 100*39. This gives the 



formula 3R Si -f. R 3 Si. It is a variety of Vosgite, containing how- 

 ever three times as much lime and much less alkali, with a specific 

 gravity about 0*04 less. 



Sf.com, Series, Vol. VII, No. 19.— Jan., 184P. 15 



