276 Kurtz and Washington — Forms of Arkansas Diamonds. 



free from inclusions. Its form was noted above. Another 

 stone weighs 6£ carats, several about 5, 4, or 3, and from this 

 they run down to ■£■$ carat, the average being probably about 

 one carat. 



Inclusions are present in some of the stones, especially in 

 the gray ones, and are apparently mostly of hematite, and in 

 one case of what appear to be rutile needles. Several of the 

 diamonds show rough and irregular indentations, as if they 

 had formed or been attached to surfaces that were not smooth ; 

 while a very large proportion, possibly one half, are fractured. 



While most of the diamonds have been found on the sur- 

 face of the igneous area, a few have been found among the 

 concentrates derived from washing the decomposed peridotite, 

 which much resembles that of Kimberley, and one diamond 

 was found embedded in the decomposed peridotite itself. The 

 portion of this that is visible is 9*l mm long and 3 mm wide, and 

 the stone is apparently a distorted and elongated hexoctahedron, 

 with much rounded faces, grayish in color. The evidence 

 seems conclusive that the diamonds found are derived from 

 the peridotite ; and, if so, this is evidently the first occurrence 

 of diamonds in place on either the North or South American 

 Continent. 



New York, Aug. 12, 1907. 



