A. J. Moses — Crystallization of Luzonite. 



281 



but in crystal No. 3 c is bright and the color is still reddish 

 steel-gray. Tarnish does not seem to explain it, as enargite 

 usually tarnishes a blue-black, and finally the possible deposi- 

 tion of a thin layer of dark-colored enargite observed on pyrite 

 associated with Morococho enargite seems not to explain, since 

 the cleavage on No. 3 is also of the dark gray color. 



2. Crystallized Wolf ramite from Ho aider Co., Col. 



Mr. Morris K. Jones, of Boulder, Colorado, sent me a sack 

 of tungsten ore from different lodes in the property of the 

 Great Western Exploration and Reduction Co., situated about 

 twelve miles west of the city of Boulder. 



The mineral, which varies in the percentage of manganese 

 in the different lodes, occurs in most of the specimens as the 

 cementing material of a brecciated rock composed chiefly of 

 fine-grained quartz and partially decomposed feldspar. The 

 spaces between the angular rock fragments are filled with the 



crystalline black ore, the crystals often crossing the crevices. 

 Occasionally the ore thickens to a considerable mass. 



On breaking the specimens numerous black brilliant little 

 crystals were found, rarely exceeding 1-J to 2 imn in their 

 longest dimension. So far as observed none of the crystals is 

 doubly terminated in the direction of the b axis, but all have 

 grown out in that direction from the mass. This and the 

 frequent existence at the visible end of a rectangular face or 

 cleavage b — 010 suggests at first examination a simple com- 

 bination of the three pinacoicls. The actual form, however, is 

 that shown in figure 5. 



Two crystals, each ending in a b cleavage and essentially 

 alike in habit, were measured. Crystal No. 1 was f X i X f mm 

 in the directions a, 5, c , and crystal No. 2 a trifle larger. 



The forms identified by the measurements were: 



Prismatic zone — l = 210 ; m, = 110 ; b = 010 ; all yield- 

 ing good signals from bright decided faces of both crystals. 



In addition a signal was obtained from both crystals which 

 closely corresponded to d — 310. It was, however, evidently 

 a second element in the striatums upon the faces l — 210. 



