4:0 Bowles — Pyromorphite from British Columbia, Can. 



Art. YII. — Pyromorphite from British Columbia, Canada /* 

 by O. Bowles. 



Introduction. — During the summer of 1907 Prof. W. A. 

 Parks of the University of Toronto visited the Society Girl 

 Mine in Southeastern British Columbia, situated a short dis- 

 tance east of the famous St. Eugene Mine in the Moyie Dis- 

 trict. Here he collected a large number of well-crystallized 

 specimens of pyromorphite, which were brought to the Min- 

 eralogical Laboratory of the University of Toronto, where the 

 writer was permitted to investigate them. 



General description. — In this locality the pyromorphite is 

 found in association with galena and cerussite in the fractured 

 country rock. The cerussite and pyromorphite appear to be of 

 secondary origin through the decomposition of galena. in frac- 

 ture cavities. A white clay surrounding the pyromorphite 

 crystals suggests the probable action of percolating water, 

 which may have supplied the phosphorus from organic matter 

 at higher levels. 



The mineral occurs in the form of densely crowded crystal 

 aggregates. Most of the crystals are wax-yellow in color, 

 while some are green ; and these two varieties exhibit some 

 interesting differences which are described later. The crystals 

 are brittle, of a resinous luster, and in their property of light 

 transmission vary from opacity or sub-translucency in the 

 larger to clear transparency in many of the smaller ones. 



Crystallography. — The crystals are of one type only, being 

 prismatic or slender acicular in habit. They occur in three 

 ways : (1) as separate individuals, (2) in radiating groups, or (3) 

 in tapering barrel-shaped aggregates. In some instances the 

 minute radiating crystals, crowded together over the surface, 

 possess a moss-like appearance. The needles may attain a 

 length of an inch or more, but those having faces sufficiently 

 bright to permit measurement with any degree of accuracy 

 are of almost microscopic dimensions. As the crystals are 

 very brittle and easily broken, it was a matter of some diffi- 

 culty to obtain specimens with terminal faces. In small, 

 well-protected pockets a considerable number were found, and 

 about forty-five were studied carefully on the two-circle goni- 

 ometer of the Goldschmidt type. 



Pyromorphite belongs to the hexagonal-bi pyramidal class. 

 The forms observed by me are as follows :- 



c {0001 |, mJlOlO}, a {1120}, a {1011}, y {2021} 

 7t {4041}, e {3034}, (See fig. 1) 



*The data contained in this paper were embodied in a thesis accepted by 

 the University of Toronto for the degree of Master of Arts. 



