198 



NEW YORK STATE MUSEUM 



Fluorite 



RossiCj St Lazvrence co. 



Among the specimens in the New York State Museum collection 

 is one worthy of notice, collected by the late Prof. Ebenezer 

 Emmons, from Rossie, St Lawrence co. This specimen which 

 measures 9 by 5 centimeters consists of a mass of rhombohedral 

 calcite on which are implanted several compound crystals of fluorite 

 of unusual habit. 



These latter are built-up aggregates, roughly octahedral in shape," 

 composed of minute individuals of hexoctahedral habit grouped 

 in parallel position. The octahedral angles of the aggregates are 

 in every case terminated by well developed superposed hexoctahe- 

 dral crystals as shown in figure 2. The compound crystals are 



Fig. 2 Fluorite, Rossie 



transparent, light green in color and average 15 millimeters in 

 diameter. They are evidently of the same generation as the calcite 

 in which they occur and are associated with chalcopyrite in well 

 developed crystals. Measurements on three isolated crystals 

 yielded the following forms: a (100), 0(1 11), v(73i) and 



