AET. 11 



EOSSITE AND METAEOSSITE FOSHAG AND HESS 



o (001). The basal pinacoid was found on all of the crystals measured and 

 is usually the only terminal face present. Very often it is smoothly curved. 



& (010). The brachypinacoid is always the most prominent face in the prism 

 zone and is always bright and smooth. 



a (100). The macropinacoid is always present, but is variable in size, ranging 

 from broad to narrow. Its relative size is dependent upon the size of the unit 

 prism. 



m (110). The unit prism is usually present as a medium to broad face, but 

 may be absent. Next to the clinopinacoid it is the most prominent face on the 

 crystals. 



A 



B 



Fig. 1. — A and B, Crystal habit op eossitb 



There are no other faces present in the prism zone. Those present are always 

 sharp, without striations, but some are slightly curved. 



y (lOl). The face of the macrodome is present on some crystals but is 

 usually smoothly curved so that accurate measurement was impossible. It is 

 often present as a small triangular terminal face, but sometimes becomes as 

 prominent as the base. 



The crystals of rossite are commonly of a prismatic habit (fig. 1), 

 but a habit tabular to the base was found in one lot of crystals. The 



