396 PHYSIOGRAPHY. CLASS II. 



GENUS IX. CHROME-ORE. 

 1. OCTAHEDRAL CHROME-ORE. 



Prismatic Chrome-Ore. JAM. Syst. Vol. III. p. 185. 

 Prismatic Chrome-Ore or Chromate of Iron. Man. p. 243. 

 Chromate of Iron. PHILL. p. 240. Chromeisenstein. 

 WEEN. Hoffm. H. B. III. 2. S. 226. Chromeisenstein. 

 HAUSM. I. S. 252. Eisenchrom. LEONH. S. 354. 

 Fer chromate'. HAUY. Traite', T.IV. p. 129. TabLcomp. 

 p. 99. Traite', 2de Ed. T. IV. p. 130. 



Fundamental form. Hexahedron. Vol. I. Fig. 1. 

 Simple form. 6, Vol. I. Fig. 2. St Domingo. 

 Fracture uneven, imperfect conchoidal. 



Lustre imperfect metallic. Colour between iron- 

 black and brownish- black. Streak brown. Opake. 



Brittle. Hardness z= 5-5. Sp. Gr. = 4498, a 

 variety from Stiria. 



Compound Varieties. Massive : composition gra- 

 nular, the individuals being of various sizes, and 

 generally firmly connected; they are often enve- 

 loped in a talcose stratum. 



OBSERVATIONS. 



1. The octahedral Chrome-ore consists, according to VAU- 

 QUELIN and KLAPROTH, of 



Oxide of Chrome 43-00 55-50. 



Protoxide of Iron 34-70 33-00. 



Alumina 20-30 6-00. 



Silica 2-00 2-00. 



Alone it is infusible before the blowpipe, but acts upon the 

 magnetic needle, after having been exposed to the reducing 

 flame. It is difficultly but entirely soluble in borax, and 

 imparts to it a beautiful green colour. 



2. The varieties of the present species frequently occur in 



