TAB. LXXXV. 



ST ANNUM ox} r genizatum. 



Oxide of Tin, in Crystals with 8-sided 

 Pyramids. 



Etain oxyde opposite. Haiiy, v. 4. 141. 



This is a rare modification. It is an incomplete 8-sided 

 pyramid placed upon a 4-sided prism, at an angle of 155° 

 according to Rome de ITsle, and of 158° 45' 27" according 

 to Haiiy. 



This pyramid is always terminated by another 4-sided 

 one parallel to the octae'dron. They either stand on the 

 gangue upright, with one end only finished pyramidally, as 

 appears from the middle figure on the right hand, which is 

 a large and curious detached crystal : being broken at the 

 top, it gives an indication of a point, but on examination 

 we find it cased on an octaedron, which probably it once 

 covered regularly ; or they lie on their sides and are pointed 

 at both ends : see the left hand figure. They are seldom 

 large. The gangue is as usual to tin crystals, viz. rock 

 crystal, chlorite, and chlorite schist, or killas of the Cornish 



