442 BULLETIN 131, UNITED STATES NATIONAL MUSEUM 



Recalculated analysis of ludwigite 



MgO 



FeO. 



A1 2 3 2.21.. 

 B2O3 15.50. 

 Fe203 



Total. 



Analysis 

 recal- Theory 

 ciliated 



38.69 ! 37.26 



5.46 5.38 



I 17.71 17.48 



38. 14 1 39. 88 



100.00 ! 100.00 



The occurrence of the ludwigite has not been studied at the locality, 



the mineral having been first identified in a specimen in the National 



Museum. 



BARITE (719) 



BARYTES, HEAVY SPAR 



Barium sulphate, BaSCV Orthorhombic. 



The following localities for the mineral barite have been noted in 

 Idaho. The only one having any prospective commercial importance 

 is in Blaine County. The mineral has a limited market, being used 

 in the manufacture of paint pigments and barium chemicals. 



ADAMS COUNTY 



In the Red Ledge mine in the Seven Devils district barite is an 

 important gangue mineral and a constant associate of the highest 

 grade ore. A typical lot of ore had a total insoluble residue of 32 

 per cent, 21 per cent of which was barite. 44 



BLAINE COUNTY 



A remarkable deposit of barite was discovered at the head of Deer 

 Creek 9 miles north-northwest of Hailey and about 7 miles from the 

 railroad at the mouth of Deer Creek, by Prof- L. G. Westgate, of the 

 United States Geological Survey. This is a lenslike mass 50 feet, 

 thick and 1,000 feet long tying apparently conformably with the 

 Pennsylvanian quartzites and calcareous sandstones of the region 

 which strike north 50° west and dip 55° northeast. It crops out 

 1,400 feet above Deer Creek Valley at an altitude of 7,400 feet. The 

 whole body is composed of white crystalline barite marked with 

 brownish bands. 45 



BOISE COUNTY 



Barite has been noted in small amount in a specimen of gold ore 

 from the Carroll-Driscoll mine in the Quartzburg district. The 

 specimen is a rounded nodule from a sericite gouge and consists of 

 quartz containing a peculiar grayish purple mineral which was 



« D. C. Livingston and F. B. Laney. Idaho Bur. Mines and Geol., Bull. 1, p. 52, 1920. 

 « TT. P. Oeol. Survey, Mineral Resources of United States, 1915, pt. 2, p. 172. 



