4:56 Lindgren and Hillebvand — Minerals from Arizona. 



brownish or greenish spreading mases were found, containing 

 brownish yellow, silky fibrous seams. The enclosing material 

 consists largely of the same material as the seams, but impure 

 and mixed with a little chlorite and pyrite. The whole bears 

 evidence of being a product of oxidation of some contact 

 metam orphic mineral. 



The fibrous mineral on the seams forms a felted aggregate as 

 seen under the microscope, but it is well individualized and 

 contains few impurities except a little pyrite and chlorite. The 

 minute fibers are brownish yellow and slightly pleochroic, being 

 darker when parallel to the principal section (opposite the 

 behavior of biotite) ; the birefringence is strong and extinction 

 strictly parallel to the fibers. No mineral corresponding to 

 this has been described, but, although its individual character 

 is beyond doubt, the analysis does not lead to a satisfactory 

 formula. The material for the analysis was picked out care- 

 fully under the lens and, examined under the microscope, it 

 proved satisfactorily pure. 



The analysis afforded the results of the first column of figures 

 below. In deducing the molecular ratios of the second column, 

 there has been deducted sufficient lime to form apatite with 

 the phosphoric oxide. 



Si0 2 



Ti0 2 



A1 2 3 



Fe O 



45-74 

 trace 



1-98 

 29-68 

 0-88 

 trace 

 1-61 

 3-99 

 0-20 



o-io 



8-84 

 0-12 ) 

 4-27 V 

 0-69 ) 



. little 

 0-66 



. 0-18 



757 



019 

 186 



011 * 



027 

 100 

 002 

 001 

 491 



Molecular ratios. 

 = 10-71 or 11 



-205 = 2-90 " 3 



FeO 



MnO ._ 



CaO 



MgO 



KO 



► 141 = 2-00 " 2 



Na 9 0__._ 



H 2 Ol05° 



= 6-96 " 7 



H 0150° 





H 2 below redness.. 



H 2 redness 



CuO 



FeS 2 



282 = 3-99 " 4 



PA 





98-89 



It would seem from the temperatures at which the water is 

 driven off that this must exist in two conditions, and that four- 

 elevenths of it must be held more securely than the remaining 

 seven-elevenths. The attempt to account for four molecules of 

 water as constitutional, however, led to no simple or seemingly 



