AM E SITE AND CORUNDOPHILITE— SHANNON. 



375 



preceding paper. Abundant material for analysis was supplied from 

 the Abert collection in the United States National Museum, The 

 specimen (Cat. 20,289) was collected at the mine by J. T. Ames, 

 after whom amesite was named. It consists of a mass of granular 

 emery coated on one side with a layer of deep-green corundophilite 

 crystals, over and aromid which is a layer of pearly diaspore. The 

 individual corimdophilite crystals reach an extreme diameter of 8 

 ■mm. with a length of 5 mm. They are greenish black in color, with 

 deeply striated prismatic planes. The cleavage surfaces are clear 

 .and brilliant and do not display any metalhc or pearly luster except 

 where bruised or weathered. Selected clean crystals were ground 

 for analysis and the analyzed powder was shown by optical study to 

 be pure and free from inclusions. The analysis yielded the following 

 Jesuits: 



Analysis of corundophilite from Chester, 3fassachusetts. 



This analysis serves to confirm those previously made upon 

 «cormidophilite from this locality, and to indicate that the material* 

 here described is typical. It also indicates that this chlorite varies 

 in composition within very narrow limits and emphasizes the differ- 

 ence between cormidophilite and most other members of the group. 

 The ferric oxide content is noteworthy, as it seems to have been over- 

 looked by several previous analysts, total iron being calculated as 

 ferrous oxide, and erroneous ratios were consequently obtcdned for 

 miivalent and trivalent oxides. The above analysis yields the follow- 

 ing ratios: 



Ratios of corundophilite. 



