W. E. Hidden — Sperrylite in North Carolina. 381 



Art. XXX VI. — Occurrence of Sperrylite in North Carolina; 

 by W. E. Hidden. 



Sperrylite was first observed by the author at the new 

 locality in North Carolina in September, 1891, but the quantity 

 found was so minute that no announcement was then made. 



The presence of this rare platinum arsenide has, however, 

 been proved to be rather widespread in the immediate vicinity 

 of the first discovery and its general occurrence in meagre 

 amounts throughout the region seems now established. 



It was found first at the mouth of the " Ned Wilson Branch " 

 of Caler Fork, a prong of Cowee Creek, in Macon County, 

 North Carolina, while the writer was testing some corun- 

 diferous gravel as to the possible presence of gold. The 

 place is locally asserted to have yielded, many years ago, a 

 sample of fine-grained gold to Robert Caler, the first white set- 

 tler of the Cowee Yalley. 



The writer soon discovered some small grains of gold and by 

 re- washing a rather large amount of gravel, that had been 

 already washed and examined for corundum, a concentrate was 

 obtained that yielded gold enough to weigh and to have 

 assayed* and also the crystals which were later recognized as 

 being sperrylite. 



It was the microscopic examination of the particles of gold — 

 in an endeavor to learn if they had traveled far, or origi- 

 nated locally — that led to the discovery of the associated sper- 

 rylite. Many hours of patient labor were expended, in the 

 finding and complete separation of the minute crystals of 

 sperrylite from the concentrate. This was largely composed 

 of minute grains and crystals of monazite,f which were bril- 

 liant yellow and transparent ; zircon, in colorless brilliant crys- 

 tals and nodules ; menaccanite, as very bright smooth black 

 grains ; rutile, as clear red highly polished particles, and gold 

 as minute flat grains and as nuggets. It was noticed that the 

 sperrylite occurred in nugget-like masses, as well as in the 

 form of cubo-octahedrons and that many of the crystal edges 

 were rounded (though not by abrasion). The luster of the 

 sperrylite is nearly like that of mercury, but in some lights a 

 color and appearance like that of dark sphalerite was observed. 

 The crystals were entirely opaque even on very thin, broken 

 edges. The occurrence in an old alluvial gravel, along with 

 gold ; the lack of any evidences of oxidation, or other chem- 



*Its " fineness " was 0-901, which is much above the usual average of North 

 Carolina gold. 



fThis monazite has been proved to contain only 0*03 per cent Th0 2 . 



