48 BULLETIN 118, UNITED STATES NATIONAL MUSEUM. 



made to the very complete exhibit of rocks and minerals from the 

 South African mines presented to the National Museum by Mr. Wil- 

 liams and described on page 134. 



Diamonds were discovered in the Urals in 1829. They occur in the 

 gold washings of the detritus along the Adolfskoi Creek, near Disersk, 

 and elsewhere along the western declivity of the Uralian range. In 

 Australia they are found in the alluvial of the Cudgegong River, near 

 Mudgee; and in the valley of the Horton River, in the Bingera 

 district of New South Wales. 



A few crystals have been occasionally met with in the United 

 States in Rutherford, Franklin, Mitchell, and McDowell counties, 

 North Carolina; in Hall County, Georgia; in Kentucky, Ohio, Wis- 

 consin, Colorado, and Idaho ; and in the placers of Eldorado, Amador, 

 Nevada, Butte, Trinity, and Del Norte counties, California. In 1856 

 the Dewey diamond, weighing when cut 11£ carats, was found at 

 Manchester, near Richmond, Virginia. 



Diamond-bearing peridotites are at present being exploited in 

 Pike County, Arkansas, and in microscopic forms have been re- 

 ported from a peridotite in British Columbia. The commercial 

 possibilities of these sources have not as yet been demonstrated. 



LIST OF SPECIMENS. 

 INDIA. 



102 small stones and 17 chips; brilliant; colorless, very clear; total weight 

 18.25 carats. Gift of the Imam of Muscat No. 1848 



SOUTH AFRICA. 



Five rough crystals, 3 white, one yellow, one brown; total weight, 1.52 carats. 

 Gift of Gardner F. Williams No. 1000 



UNION OF SOUTH AFRICA (KIMBERLEY, GRIQUALAND WEST). 



Partly cut; colorless; 1.67 carats; 5 by 5 by 5 No. 467 



Uncut; gray; 1.6 carats; octahedron, 5 by 5 mm. The Shepard collection. No. 1001 



Brilliant, rectangular girdle; colorless; 0.928 carat; 6 by 5 by 4 mm No. 466 



Brilliant, circular girdle; white; 0.25 carat; 4.5 by 3.5 mm. Isaac Lea 



collection No. 470 



Brilliant, circular girdle; yellow; 0.19 carat; 4 by 3.5 mm. Isaac Lea 



collection No. 471 



Brilliant, circular girdle; brown; 0.15 carat; 4 by 3 mm. Isaac Lea 



collection No. 472 



Brilliant, circular girdle; green; 0.14 carat; 3 by 3 mm. Isaac Lea collec- 

 tion No. 469 



Brilliant, circular girdle; pink; 0.13 carat; 4 by 3 mm. Isaac Lea collec- 

 tion No. 468 



UNITED STATES. 



Kentucky. 



Cabin Fork Creek, near Montpelier, Adair County: 



Uncut but polished; yellow; 0.776 carat; 8 by 4 by 3 mm. Isaac Lea 



collection No. 465 



