W. H. Melville — Josephinite, a new Nickel-Iron. 509 



Art. LXIII. — Josephinite, a new Nickel-Iron • by W. H. 



Melville. 



History. — Several months ago Prof. F. W. Clarke sub- 

 mitted to me for examination a quantity of magnetic pebbles 

 which were sent to this office by Mr. Wm. H. Hampton of 

 Portland, Oregon, and by subsequent correspondence with 

 this gentleman he obtained a larger amount with full liberty to 

 publish the results arrived at in the laboratory. 



In the spring of 1891 Mr. Hampton discovered these pebbles 

 in large quantities in the placer gravel of a stream in Jose- 

 phine and Jackson Counties, Oregon, which border on the 

 south of Douglas Co. where the nickel silicate* described by 

 Prof. Clarke occurs. He analyzed with reference to nickel 

 and iron an average sample of twenty pounds of the wash 

 gravel from the placer diggings, and found that the metallic 

 portion gave 60*3 per cent nickel and 26*7 per cent iron. 

 From the nature of the gangue or stony portion Mr. Hampton 

 concluded that these waterworn pebbles and bowlders — for 

 some pieces weighed over one hundred pounds — " came from 

 an eruptive dike somewhere in the vicinity." The locality of 

 this dike was not at that time ascertained. 



Physical Characters. — The pebbles are irregular in shape 

 but approximate the form of ellipsoids. Their smooth sur- 

 faces, polished by the action of water, are colored in general 

 greenish black, interrupted by bright areas of the grayish white 

 alloy of nickel and iron. The former portions consist of 

 siliceous matter and when cut by a knife yield a dull and light 

 gray powder, but broken fragments show greenish yellow and 

 deep green colors and resinous luster resembling noble serpen- 

 tine. With this is associated in some pebbles a silicate whose 

 hardness is between 5 and 6. It is compact and on the fresh 

 fracture exhibits a light brown color and vitreous luster, while 

 exposed surfaces are reddened by ferric oxide. 



The texture of the metallic portion as it appears on fracture 

 is granular. The metal is gray, malleable and sectile with 

 hardness about 5. 



The specific gravity of one lot containing forty-two pebbles 

 was taken in a pycnometer at a temperature of 22° C. These 

 pebbles ranged in weight from 0*3159 to 1-6417 grams and 

 were about the dimensions of a pea. The largest pebble in 

 my possession weighed 1*2817 grams, and the specific gravity 

 of this was made by suspending it from a silk fiber. Two 

 determinations furnished a mean specific gravity of 6*204. 



* Bulletin No. 60, U. S. Geol. Survey, p. 21, 1887-1888. 



