242 G. W. McKee — Prismatic Crystals of Hematite. 







Crystal No. I. 









Measured. 



Calculated. 





No. 





•« 



A 





Symbol. 



P 



4> 



P 



<*> 



1 



0° 







0° 







{0001} 



2 



90° 



0° 15' 



90° 



0°~) 





3 



90° 



0° 2' 



90° 



0° | 





4 

 5 



90° 

 90° 



0° 8' 

 0° 15' 



90° 

 90° 



0° ' 



o° r 



{1010} 



6 



90° 



0° 10' 



90° 



0° 





7 



90° 



0° 8' 



90° 



0°J 





8 



72° 21' 



29° 52' 



72° 22' 



30° 



{2241 } 



9 



38° 36' 



28° 2' 



38° 11' 



30°] 





10 



37° 15' 



27° 46' 



38° 11' 



30° | 





11 



38° 24' 



30° 25' 



38° 11' 



30° y 



{1122} 



12 



37° 15' 



30° 40' 



38° 11' 



30° j 





13 



40° 6' 



28° 55' 



38° 11' 



30°J 









Crystal No. II. 









Measured. 



Calculated. 





No. 





A 



It 





Symbol. 



r 



■\ 



r 



■> 





P 



<£ 



P 



<t> 





1 



0° 







0° 



. 



{0001} 



2 



90° 



0° 14' 



90° 



o> | 





3 



90° 



0° 2' 



90° 



0° | 





4 



90° 



0° 17' 



90° 



o° y 



{1010} 



5 



90° 



0° 3' 



90° 



0° | 





6 



. 90° 



0° 1' 



. 90° 



0°J 





H 



i 



8 



72° 22' 

 72° 22' 



29° 31' 

 29° 45' 



72° 22' 

 72° 22' 



30° ) 

 30° \ 



{2241} 



9 



12° 30' 



29° 45' 



11° 7' 



30° 



{1128} 



The accompanying drawing, fig. 1, was prepared from a 

 gnomonic projection showing the projection points of the 

 normals of an idealized crystal representing all the forms 

 obtained. The relative central distance for the different forms 

 indicated in the drawing corresponds very closely with that of 

 the crystals examined. 



Hematite crystals showing the prismatic habit have been 

 described by Pirsson.* His specimens were also obtained 

 from Mexico and were peculiar in their association with cassit- 

 erite, which w r as frequently contained in the hematite as inclu- 

 sions. Some of the Guanajuato crystals were finely powdered 

 and treated with hot concentrated hydrochloric acid ; the 

 resulting solution was tested in the usual method and was 

 found to be free from tin. 



These observations were made in the Mineralogical Labora- 

 tory of the University of Toronto. 



* This Journal, vol. xlii, pp. 407, 1891. 



Department of Mineralogy, University of Toronto, 

 December, 1903. 



