Davison Whitfield Iron 91.65 91.46 Nickel 7.88 8.30 Cobalt .21 ? Phosphorus .09 ? ————— ————— 99.83 99.76 The famous Cañon Diablo meteorite possesses a surpassing mineralogical interest.[181] In 1891, at the Tenth International Geologic Congress, Washington, D. C., the mineralogist Koenig announced that he had discovered some microscopic diamonds in this meteorite, and later investigations by Prof. Henri Moissan confirmed this discovery and enlarged its scope. A mass of the iron weighing about 400 pounds was used by Professor Moissan; this was cut by means of a steel ribbon saw. As had been the case in Koenig’s investigations, the saw soon encountered excessively hard portions that obstructed its operation, so that twenty days’ labor was requisite to separate the iron into two parts, each with a section area of nearly 100 square inches. On close examination it became evident that the obstacles to the cutting consisted of round or elliptical nodules, of a dark gray to black hue, and enclosed in the bright iron. These nodules were mainly composed of troilite (iron protosulphide). After chemical treatment an insoluble residue remained, consisting of silica, amorphous carbon, graphite and diamond. Many of these very minute diamonds were black, but a few were transparent crystals, octahedrons with rounded edges.[182] The presence of this diamond material in the interior of the iron mass of the meteorite indicates their formation from carbon by the combined agencies of high temperature and great pressure, as in the case of the artificial diamonds experimentally produced by Moissan in an iron mass first subjected to intense heat in the electric furnace and then rapidly contracted in volume by sudden chilling. The fervid imagination of early writers would certainly have attributed wonderful talismanic powers to stones like these, probably generated in some lost planet and reaching our earth through the wastes of celestial space, could they have been able to observe and distinguish them with the incomplete optical resources of their time.