194 BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



are rough, imperfect, and worn. Usually they are simple hexagonal 

 prisms terminated by a basal pinacoid, but some are double hexag- 

 onal pyramids. Some of them are coated with a white pearly mica 

 which proved, upon microscopic examination, to be muscovite, and 

 in the side of one corundum crystal a crystal of black tourmaline is 

 embedded. 



CUSTER COUNTY 



Corundum is reported to occur in gold placers in Stanley Basin in 

 Custer County. 



IDAHO COUNTY 



Corundum is found near Resort in Idaho County in gold placers. 

 Three crystals from this locality have been examined. The first of 

 these is a large opaque tapering hexagonal pyramid 2.5 cm. in diameter, 

 the second a small hexagonal prism 1 cm. long by 8 mm. thick of 

 pinkish gray color and the third a hexagonal table 1.5 cm. across 

 having a fine bronze color and chatoyant luster. 



WASHINGTON COUNTY 



Corundum is found in concentrates from the Rock Flat gold 

 placer near Meadows The corundum is abundant associated with 

 numerous garnets. In color the gray to amethyst shades pre- 

 dominate, although pink crystals yielding cut stones up to 1 carat 

 occur and cornflower blue stones of from one-half to 1 carat could 

 be cut from some. A few rubies of poor quality have been found. 

 Much of the corundum has a silky sheen or is opalescent and would 

 yield star sapphire or cat's-eye. Many of the crystals are fine bronze 

 and the larger crystals often have blue ends. 98 The value of the gems 

 sold in 1906 from here is estimated at $300, the most valuable single 

 stone being a pink gem of 13^ carats, valued at $20." 



HEMATITE (232) 



RED IRON OXIDE 



Iron sesquioxide, Fe 2 3 . Rhombohedral. 



ADAMS COUNTY 



In the Seven Devils district the specularite variety of hematite is 

 abundant in the contact copper ores. It is found as thick curved 

 scales scattered through massive bornite, and in some specimens as 

 thin plates parallel to the faces of garnet or epidote crystals. 1 The 

 mineral is abundant in massive epidote, especially in the more 

 quartzose portions of the veins. In specimens from the Copper 

 Boy dump, specularite forms broad, lustrous plates, and sheaves in 

 epidote. In the ore from the Peacock mine, large, curved hematite 



99 Robert N. Bell. Mining Industry of Idaho. Rept. State Mine Inspector for 1906, p. 171. Boise. 

 98 U. S. Qeol. Survey. Mineral Resources for 1906, p. 1230. 

 1 C. Palache. Amer. Jour. Sci., vol. 8, p. 302, 1899. 



