HUNTINGTON. — DIAMONDS IN METEORITES. 205 



form of graphite in the Arva iron, described so long ago by Haidinger, 

 and the cliftonite found by Fletcher in the Youndegin iron, but 

 makes no mention of Weinschenk's description of colorless transparent 

 diamonds in the Arva iron. 



The Mineral Cabinet of Harvard University was presented, through 

 the liberality of Francis Bartlett^ Esq., with one of the original 

 masses of the Canon Diablo meteorite, and it was at once examined 

 for diamonds. A piece weighing one hundred grams was dissolved in 

 acid, and, after the usual process of getting rid of the carbon, silica, etc., 

 a small quantity of fine powder was separated by its higher specific 

 gravity and examined under the microscope. It appeared to be made 

 up of dark and light grains, the latter showing unmistakably the lustre 

 of the diamond. The colorless particles were separated mechanically 

 upon the stage of the microscope, and looked to the eye like white 

 beach sand. One of these grains was mounted in the point of a 

 metallic lead pencil, and it wa9 found that, though so small, it would 

 readily cut glass with the characteristic singing noise of a glass-cutter's 

 diamond, and it would also readily mark upon a polished sapphire. 

 There was not enough of the clear material obtained at the time for a 

 chemical test, and on accouut of the association of the diamond grains 

 with amorphous carbon, such a test would not have been conclusive 

 without a perfect mechanical separation. 



This seemed at the time sufficient proof that the material was 

 diamond, and a portion of it was exhibited before the meeting of the 

 American Academy of Arts and Sciences on May 11, 1892, and at 

 that time the author showed a large nodule of graphite from the 

 Sevier County iron and said : — 



" As is well known, graphite separates from melted cast iron when 

 it slowly cools, and the connection of these masses with the iron 

 meteorites indicates that they also were formed by the slow cooling of 

 masses of melted iron, very possibly thrown up by volcanic action 

 from the interior of some planet. The high specific gravity of the 

 earth suggests the conjecture that its interior is a mass of iron, and 

 the metallic iron which has been found in the deep-seated eruptive 

 rocks, as in Greenland and the South of France, gives support to the 

 hypothesis that these rocks may be the matrix of the diamond, and 

 that the diamond crystals may have separated during slow cooling 

 from the melted metal forced up from below. 



« Thus : — 



" Graphite separates out from meteoric iron. It also separates 

 during the cooling of cast iron. 



