102 JOUKNAL OF THE MlTCHELL SoCIETY [^AuQUSt 



MONAZITE 



The discovery tihat thoria would make a much better in- 

 candescent mantle for lighting purposes than zirconia made 

 it necessary to discover commercial deposits of some mineral 

 containing a considerable percentage of this compound. The 

 mineral that offered the best chance of furnishing this salt 

 was mjonazite, which had been discovered in 1879 by W. S. 

 Hidden '''. Prospecting was carried on quite vigorously for 

 this mineral, chiefly in North Carolina, with the result that it 

 was found in considerable quantity. Since this first discovery 

 the IS^orth Carolina areas containing this mineral in quantity 

 have been very largely extended and it has also been found in 

 South Carolina. 



The first commercial shipment of monazite was in 1887, 

 and the production was continued each year until 1910, but 

 since then no production. 



Monazite also furnishes ceria (CeO), another salt that is 

 used in very small amount in the manufacture of incandescent 

 mantles ; and is also used by pharmacists. 



OCCURRENCE 



Monazite is found vtrj widely distributed as an accessory 

 constituent in varviiig proportions of many granites and their 

 derived gneisses. Thus it has been found in the porphyritic, 

 granulitic, and schistose gneisses of the Maritime Mountains 

 of Brazil, extending for a distance of 300 miles through the 

 l^rovinces of Bahia, Minas-Geraes, Rio de Janeiro, and Sao 

 Paulo ; and in the granitic mica-gneisses and hornblende-gneis- 

 ses of the South Mountain region of ISTorth Carolina, cover- 

 ing an area of some 3,000 square miles in McDowell, Burke, 

 Caldwell, Rutherford, Cleveland, Polk, Catawba, Iredell, Alex- 

 ander, Lincoln, and Gaston counties, and extending into Spar- 

 tanburg, Lawrence, Greenville, Pickens, Anderson, Oconee, 

 South Carolina. Although occurring in but small quantity it has 

 been identified in the granites or gneisses of Maine, I^ew Hamp- 

 shire, Massachusetts, Rhode Island, Connecticut, ISTew York, 



'Am. Jour. Sci., (3) vol. 21, 1881, p. 159, and (3) vol. 32, 1886, p. 207. 



