Mineral Sulphides of Iron. 

 Measurements of a-PYRRHOTiTE 



229 



IK 



T— 1 



o 



o p o 



o 



o 



o, p o 



o 



8, Po 



Average 

 p =c. 



Other measured 

 angles 









43° 50' 0-9610 



0-9834 

 0*9850 

 0-9578 

 0-9639 



0-9376 

 0-9380 

 0-9732 

 09725 



l-0035± 



0-9878 

 0-9827 

 0-9667 

 0-9927 

 0-9891 

 0-9669 



0-9521 

 0-9530 



0-9578 



0-9660 



0-9267 



0-9485 























44° 10' 0-9713 







(001)(021) = 32° 27' 









61° 48' 0-9372 







(001) (221)=z74°59' 

 (001)(992) = 83°41' 









0*9701 



62° 44' 0-9750 



63° 24' 1-0035 

 63° 1' 0-9878 

 62° 55' 0-9827 

 62° 32' 0-9667 

 63° 9' 0-9927 

 63° 4' 0-9891 

 62° 34' 0-9681 



62° 14' 0-9545 



43° 59' 0-9646 



43° 59' 0-9675 













(001)(091) = 83° 17' 

























0-9920 



43° 51' 0-9607 



44° 12' 0-9772 





0-9614 





0-9497 





0*9530 







(001) (07l) = 81°40' 

 (001) (0.1.20) = 2°42' 



0*9578 









0-9524 

 0-9262 



62° 40' 0-9772 

 61° 58' 0-9437 

 62° 10' 0-9517 



43° 50' 0-9601 

 43° 10' 0-9380 





0-9456 



(001)(1.1.34) = 3°10' 









of the fourth preparation are usually twinned, and the common 

 habit of these crystals is shown in fig. 20. This crystal is 

 twinned after (021) and the crystals which are twinned after 

 (023) are similar, except for the twinning law. These crystals 

 are also elongated along the a axis and show a very different 

 development in the zone {0 hi) from that in the zone {h h I). 

 Fig. 21, which is a stereographic projection of crystal IT, shows 

 the development of the zonal and vicinal faces. Several other 



