148 PHYSIOGRAPHY. 



Fracture presenting a vitreous tissue. Colour 

 flesh-red. Hardness sufficient to scratch glass. 



It is supposed by HAUY to be a variety of the hexahe- 

 dral Kouphone-spar; but the form of the octahedron having 

 never yet been observed in that species, an accurate exa- 

 mination of Sarcolite is still a desideratum. 



SAUSSURITE. 



Saussurite. JAM. Syst. Vol. I. p. 71- Man. p. 182. 

 Saussurite. PHILL. p. 135. 



Prismatic. Cleavage two faces meeting at angles 

 of 124 nearly, pretty distinct. Traces parallel 

 to the short diagonal of that prism. Fracture 

 uneven splintery. Massive : composition granu- 

 lar ... impalpable, strongly coherent. 



Lustre pearly, inclining to vitreous upon the faces 

 of cleavage ; resinous in compound varieties, par- 

 ticularly when cut and polished. Colour white, 

 passing into mountain-green, greenish- and ash- 

 grey. Streak white. 



Brittle. Very difficultly frangible. Hardness = 5-5. 

 Sp. Gr. = 3-256 of a granular variety from Pied- 

 mont, 3-342 of a compact variety from the Pays 

 de Vaud. 



Before the blowpipe it melts with difficulty into a white 

 glass. According to SAUSSURE and KLAPROTH, it con- 

 sists of 



jl Silica 49-00 44-00. 



Alumina 24-00 30-00. 



Lime . 10-00 4-00. 



Magnesia 3-75. Potash 0-25. 



Oxide of Iron 6-50 12-50. .'-.*. 



