464 Watson — Occurrence of Uranophane in Georgia. 



Art. XL. — On the Occurrence of Uranophane in Georgia; 

 by Thomas L. Watson. 



[Published by permission of W. S. Yeates, State Geologist of Georgia.] 



The object of this paper is to describe the occurrence of the 

 rare mineral uranophane from a new locality. State Geologist 

 Yeates first observed the occurrence of the yellow mineral at 

 Stone Mountain, Georgia, in the early nineties, and later had 

 Mr. E. L. Packard examine the material chemically in the 

 laboratory of the Georgia Survey. During 1898 and 1899, 

 while engaged in a field study of the Georgia granites, the 

 writer independently noted the occurrence of this mineral at 

 the same locality, as a thin, yellow incrustation coating the 

 faces of many of the joint planes cutting the Stone Mountain 

 granite mass. Specimens were carefully collected and studied 

 in the laboratory of the Survey in Atlanta. 



So far as the writer can ascertain, uranophane is reported 

 from only one locality in the United States, namely, Mitchell 

 County, North Carolina,* Here the mineral is found incrust- 

 ing and penetrating gummite as an alteration product at the 

 mica mines. Under the title " On Some New Mineral Occur- 

 rences in Canada," G. Chr. Hoffmanf of the Canadian Geo- 

 logical Survey has recently described the occurrence of 

 uranophane from Ottawa County, Quebec. According to 

 Hoffman, the mineral in Quebec is associated with " gummite, 

 uraninite, black tourmaline, white, light gray, pale olive-green 

 and bluish green apatite, spessartite, monazite, and green and 

 purple fluorite, in a coarse pegmatite vein composed of white 

 and light to dark, smoky-brown quartz, microcline and musco- 

 vite, which traverses a gray garnetiferous gneiss." The min- 

 eral is further described as an alteration product of gummite, 

 occurring iC in small bright lemon-yellow fibrous masses, some- 

 times in immediate contact with the gummite found coating 

 the uraninite or, <per se, embedded in the albite immediately 

 surrounding the tourmaline and often invading the latter." 

 In both Quebec and North Carolina the mineral is an altera- 

 tion product of gummite, and, in this particular, its occurrence 

 is similar for the two localities, while in Georgia the occurrence 

 is entirely different, as will be noted in the following descrip- 

 tion. 



At Stone Mountain, Georgia, sixteen miles east of Atlanta, 

 the mineral uranophane is found as a distinct incrustation, 

 coating the faces of many of the joint planes, which cut the 

 granite boss. It varies from a sulphur-yellow to lemon-yellow in 



*Dana, E. S., A System of Mineralogy, 1893, p. 699. 

 fThis Journal, vol. xi, pp. 152-153, 1901. 



