METEORITES OF NORTH AMERICA. 99 



Meunier * also notes that 



The schreiberaite is not uniformly distributed, large surfaces being entirely free from it, but where it is present, 

 as is usually the case, it produces the appearance and orientation of the Brazos and Sarepta masses. The etching fig- 

 ures are exactly identical with those of the Brazos iron and show like it broad bands of kamacite associated with thin 

 filaments of taenite. 



Brezina " notes that 



Among all known meteoric irons Cafion Diablo furnishes the largest number of immense blocks, weighing 500 

 kg. and upwards, although a few fall short of the large Mexican masses. Like Penkarring Rock, this iron has a ten- 

 dency to orifices from the surface, and in the case of the smaller pieces, of a few kilograms weight and upwards, to the 

 separation of sharp angled individuals, which appear almost like metallic potsherds, only much more sharply pointed. 

 Moreover, the exterior of such small individuals is divided in a most singular manner; it seems as if , in an iron fur- 

 nished with pittings, these depressions had simultaneously been enlarged until they touched and intersected one 

 another, so that only the wave-crests arising from the intersection of the very shallow cavities remained of the eleva- 

 tions between them. Frequently this peculiarity of the exterior is to be seen only on the broad side of the clod-like 

 pieces, while the other side has been rendered convex by. widespread weathering; many such pieces show that the 

 rounded side was buried in the ground, which is abundantly proved by the still adhering particles of a calcareous 

 deposit. Small fresh formations on this coating (stalactitic deposits of from 1 to 2 mm. in length) likewise show by 

 their situation that the iron flakes were imbedded with their broad sides horizontal. By weathering to limonite a 

 flat stratification (with a preference for octahedrons) is formed at times whereby frequently the remnants of the refrac- 

 tory taanite distinctly mark, the direction of the octahedral laminae, as is the case on fresh iron after etching. That is 

 to say, the triad resists the action of acid very markedly, and by the complete recession of the taenite and the indif- 

 ferent condition of the kamacite as well as the scarcity of fields, the etched iron frequently appears like an ataxite. 

 Most pieces are very refractory to etching; this is so in case of pieces composed almost entirely of kamacite, without 

 any visible taenite or other admixture. Less frequently portions occur which show ribs of cohenite in the kamacite; 

 on such pieces the kamacite is customarily more easily affected by the acid and by the employment of a more power- 

 ful acid it readily receives scratches. Occasionally huge nodules of troilite and graphite from 10 to 15 cm. in size 

 occur in the iron. 



Huntington " in 1894, published a further investigation into the occurrence of diamonds 

 in the Canyon Diablo meteorites, the tests of Friedel to this end not being deemed by him con- 

 clusive. He examined about 200 pounds of the iron, selecting the pieces most likely to afford 

 diamonds. These were then dissolved. He states: 



Most of the iron dissolved contained no diamonds whatever. One piece, however, in the process of dissolving, 

 showed an irregular vein running through it, consisting of a white vitreous substance, varying in width from a fine line 

 to nearly 4 mm. This vein stuff proved to exceed the ruby in hardness. On further examination, it appeared to be a 

 mixture of iron, a sulphide of iron, silica, amorphous carbon, and diamond, and had to be crushed to get rid of all the 

 iron. 



The hardest grains of this vein substance were isolated, and when examined under the microscope one minute 

 but perfect octahedron of diamond was found, transparent and colorless. It was separately mounted in a microscope 

 slide, but soon disappeared, and in its place were found only some very minute angular fragments. A second crystal 

 was afterwards isolated, but disappeared in like manner, suggesting that they had been formed under pressure, and 

 when exposed in a warm room, had exploded. 



About half a carat of diamond powder was finally obtained, being separated by its specific gravity from a very 

 large quantity of amorphous carbon. The particles varied from colorless through yellow and blue to black. Many of 

 them appeared to be angular fragments, though some of them looked not unlike hyalite, except for their more bril- 

 liant luster. Several perfect little octahedrons were found that did not break up. The original specimen measured 

 only a little over a hundredth of an inch in diameter, but when viewed through a two-thirds objective it showed dis- 

 tinctly the hexahis octahedral planes, the curved edges, striations, etc., adamantine luster and clear water of the dia-' 

 mond crystal. 



A newly planed wheel in the Tiffany Exhibit at the Columbian Exposition, was charged with the residue from 

 the Cafion Diablo iron, and when a rough diamond was placed upon the wheel it immediately gave out a sharp hissing 

 sound, and in a few minutes a face was ground down and polished. Two other diamonds were cut and polished in 

 the same way. In all respects the residue from the Cafion Diablo iron was found to act exactly like any other diamond 

 powder. 



These experiments were regarded by Huntington as establishing the fact that the Canyon 

 Diablo iron contains true diamonds, and not some new allotropic form of carbon. 



