BULLETIN. 



California Academy of Sciences. 



ON THE MORPHOLOGY OF COLEMANTCE. 



BY A. WENDELL JACKSON. 



In the American Journal of Science for December, 1884, I 

 published a short preliminary notice of a new borate of lime, 

 that had been discovered in the southern part of Death Valley, 

 Inyo County, California. In the present paper I communicate 

 the results of my crystallographic study of the mineral; a later 

 communication will discuss its optical and other physical prop- 

 erties. 



Mr. J. T. Evans of this Academy, who first called attention to 

 the new mineral, gives the following description in a paper read 

 before the California Academy of Sciences, February 4th, 1884: 



"Crystallization monoclinic. inclination of the vertical axis to 

 the clinodiagonal axis (C) 70^°, I A I 108£°; ii A I 144^°, ii A I 

 126^°. Luster vitreous to adamantine, often splendent. Cleav- 

 age ii or clinodiagonal, perfect, affording readily thin, smooth 

 and polished lamin?e which often show interference figures. 

 Cleavage in other planes imperfect and fracture uneven, giving 

 surfaces of a subvitreous luster. Hardness 3.5 in the amorphous 

 [massive], to 4.25 in the crystalline [crystallized] variety. Spe- 

 cific gravity 2.428. Colorless. Streak white. Transparent, sub- 

 translucent to milky, especially in the massive. Rather brittle. 



*Measurements were made with a contact goniometer. 



