On Crystallized JVative Terrestrial Iron, fyc. 141 



Olmsted's catalogue of the collection, which was published in the 

 fifth volume of this Journal. It is described as distinctly plated } 

 hard ; assuming under the file the lustre of steel ; highly magnetic ; 

 breaking under the hammer, with the lustre of steel ; and having the 

 specific gravity of 7.4. Its weight is a little short of two pounds. 

 It was found in the vicinity of a bed of Iron ore, of the argillaceous 

 kind. The smaller specimen, which weighs seven ounces, is pos- 

 sessed of the same characters in the main, though a little less brittle ; 

 but is a distinct crystal, in the form of an octahedron. Prof. Olm- 

 sted informs me that it comes from Guildford county, ten or fifteen 

 miles distant from the locality of the first specimen, which was found 

 in Randolph county. The individual from whom he obtained it, in- 

 formed him, that it was detached from a mass weighing twenty eight 

 pounds, which was wrought by a blacksmith of the neighborhood, into 

 horse-nails. The crystalline structure of this specimen is what par- 

 ticularly interested me ; for, although the existence of native terres- 

 trial iron may now be considered as established beyond all doubt, yet 

 it had hitherto been observed only in a massive state. The axis of 

 the crystal measures three inches. The angle at the summit is 60°, 

 that at the base 120°. It is, therefore, a regular octahedron. Its 

 structure is distinctly foliated, the lammse being pretty uniformly one 

 twentieth of an inch in thickness, and arranged parallel with the 

 planes of the octahedron, which must consequently be considered as 

 the primary form of the species. On one or two of the planes, the 

 laminae extend beyond the edges of the adjoining and opposite faces, 

 or those which are external do not in all cases cover the layers upon 

 wliich they rest ; but stopping somewhat short of their borders, en- 

 able us to discover the internal structure of the crystal with great 

 distinctness. 



In farther examining fragments freshly detached from these mass- 

 es, I was struck with their resemblance to the native iron from Penn- 

 sylvania, of which I gave some account in Vol. XIV. p. 183, of this 

 Journal, and which was found to contain a trifling per-centage of 

 arsenic. Having satisfied myself, by forming a solution in nitric acid, 

 that the brittleness and want of malleability in the present case, was 

 jiot owing to the presence of carbon, no carbonaceous discoloration 

 taking place ; and, moreover, being assured, by the applications of 

 the customary tests, of the absence of silver, copper, and nickel, I 

 felt no hesitation in concluding that it was identical with that sub- 

 stance* Had the compound blow-pipe been in operation, it would 



