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E. 8. Dana — Miner alogical Notes. 



Diaspore from Newlin, Penn. — Through the kindness of Pro- 

 fessor F. W. Clarke and Mr. Joseph Willcox I have had the 

 opportunity of examining a crystal of diaspore from 

 ISTewlin, near Unionville, Penn., belonging to the 

 latter. The crystal is the finest ever found at the 

 locality; it is prismatic in habit, about f inch in 

 length and doubly terminated. It showed the fol- 

 lowing planes, the vertical zone being strongly stri- 

 ated : J (010, i-i), A (210, z-2), J (120, i-2), n(150, U), 

 q (232, f-f). Of these the pyramid q is new to the 

 species; such measurements as were possible agreed 

 with the calculated angles (accepting the axes of 

 Kokscharow). Better measurements were obtained on a simi- 

 lar but very small crystal from the same locality in the cabinet 

 of Professor Brush. These angles are : 





Calculated. 



Measured. 



qq' = 232 ~ 232 = 51° 2' 

 qq" = 232 * 232 = 96° 3' 

 qq'" = 232 „ 232 = 74° 34' 



« 51° 20' 

 96° 14' 



74° 30' 



Diaspore from Chester, Mass. — The Chester diaspore com- 

 monly occurs in thin cleavage plates implanted upon the 

 magnetite gangue. Occasionally it is found in 

 very delicate acicular crystals, and again in groups 

 of crystals tabular parallel to the brachypinacoid. 

 A basal projection of the last named form is given 

 in the accompanying figure. The crystals are in 

 fact composite, consisting of parts in nearly parallel 

 position. They are deeply striated in the vertical 

 zone and also in the zone pe. The observed planes 

 are : 



a (100, i-i), b (010, **), h (210, 1-2), I (120, i-2), 

 e (011, 1-S), 5 (212, I-2), p (111, 1), u (344, 1-|), 

 v (122, 1-2). Of these u and v are new, they are determined 

 by the following measurements : 



Calculated. Measured. 



au = 67 c 



av = 74 c 



30' 

 35' 



67° 



75° 



29' 



30' approx. 



3. Zincite. 



Our knowledge of the crystals of zinc protoxide has rested 

 thus far upon observations of artificial crystals, the native min- 

 eral showing usually only massive forms with distinct basal 

 and prismatic cleavage. Early measurements of the artificial 

 crystals were given by Kose (in 1852), and since then contribu- 

 tions to the subject have been made by vom Rath, DesCloizeaux 



