Washington — Kaersutite from Linosa and Greenland. 211 



Linosa. Kaersut. 



Specific gravity 3-336 3*137 



Crystal system rnonoclinic rnonoclinic 



110^110... 55° 22' 55° 35' 



C A conllO + 1°24' —8° 9' 



Optical character negative negative 



Color,. _- deep brown chestnut brown 



Absorption c>B>a c>b>a 



a - 1'692 1*676 



/3 1*731 1-694 



y - 1-760 1-708 



y — a -068 '032 



2V-. - 79° 54' 82° 6' 



Dispersion (?) weak (?) weak 



knowledge of the true chemical composition and relations of 

 the hornblendes, the numerous varieties that are constantly 

 being observed and often named, and the fact that many well- 

 recognized species show greater divergence in physical proper- 

 ties and chemical composition than do our minerals, it seems to 

 us advisable not to bestow a new name at present on the Linosa 

 hornblende, but to consider it a kaersutite. 



In conclusion attention may be called to the somewhat 

 remarkable coincidence between the finding of kaersutite both 

 in Greenland and on Linosa, and the similar occurrence of 

 aenigmatite in Greenland and the apparently identical cossy- 

 rite on Pantelleria, which lies close to Linosa. In both the 

 Arctic and the Mediterranean localities these minerals occur 

 in comparative abundance and as material which can be easily 

 studied, while elsewhere kaersutite is unknown and aenigma- 

 tite very rare and the crystals small and unsatisfactory. 



Locust, New Jersey, and 



Geophysical Laboratory of the 



Carnegie Institution of Washington, D. C. 



