CHROMITE AND PHOTITK. 179 



opaque. Of part of the grains the reflection is dull ; Ijut of others, even of 

 the translucent parts, it is bluish metallic; structure, granular. 



Most of the isometric oxides in A. E. 209 are opaque and in irregular gran- 

 ules and crystals. Some of the larger grains are traversed by an irregular 

 network of crystalline grains, giving a bluish metallic reflection, and holding 

 interstitial portions of a dull lustre. Part of these interior portions are 

 opaque, and part are translucent and of a deep reddish-brown color. 



In A. E. 217, 473, and 216 two different kinds of ore were observed. 

 One is granular, opaque, and bluish-black in reflected light. The other is a 

 dull, earthy-brown, amorphous mass in reflected light, but translucent and of 

 a pale grayish-brown color by transmitted light. The two nre frequently 

 united in the same grain, and the first is here considered to be magnetite., 

 while the second is a limonitic product of decomposition of iron ores. 



A. E. 481 has its mineral in irregular opaque grains of a dull lustre, and 

 traversed by cracks filled with serpentine. 



A. E. 214, 270, 274, 482, 483, 483 (bis), 484, 485 have their ores all 

 opaque and granular, giving a bluish reflection. 



Through the kindness of Professors F. A. Genth and Edward S. Dana, a 

 number of chromites were obtained for examination. 



The following twenty-four were sent by Dr. Genth. All were found to 

 be translucent, most showing this with a low power, but some required a 

 high power. The color is a yellowish-brown in transmitted light, in the 

 specimens from Westfield, Vermont ; Chester, Massachusetts ; Walter Green's 

 mine, Delaware Co., Pennsylvania ; Moro Phillip's mine in Marple Township, 

 Delaware Co., Pennsylvania; Webster, Jackson Co., North Carolina; and 

 Western North Carolina.*^ 



The chromite from the Phillips mine, Nottingham, Chester Co., Pennsyl- 

 vania, is of a yellowish-brown color tinged variously with green and reddish- 

 brown. That from Media, Delaware Co., Pennsylvania, is in crystals, the 

 powder of one of which is perfectly opaque, and that of another a deep 

 yellowish-brown. In the following the color is a deep yellowish-brown and 

 a reddish-brown : Davis Moore's mine, Middletown Township, Delaware Co., 

 Pennsylvania ; Wood's mine, Texas, Lancaster Co., Pennsylvania ; the Red 

 Pit, and Low's mine from same county ; Soldier's Delight, Maryland ; Culs- 

 agee,t Macon Co., North Carolina; Hampton's, Yancy Co., North Carolina; 



* This last is from tlie specimen analyzed by Dr. Geutli as being from Franklin, Macon Co., Is'orth 

 Carolina, and containing 44.15 per cent, of chromic oxide. (See table of analyses.) 



f Tiiere -vrere two specimens from this locality, one iu octahedral crystals, the other massive. 



