Diamonds in Canyon Diablo, Arizona, Meteorites

The method of detection, appearance, hardness, etc., of carbonadoes (so‐called “black diamonds”), in Canyon Diablo, Arizona, meteorites, are described. In the past nine years, carbonadoes have been encountered in about twenty specimens. These carbonadoes were usually imbedded in nodules or veins of dark sulfide and carbonaceous material, though in some instances they occurred in schreibersite inclusions; in one case, they were associated with a small cavity which occupied the central part of a schreibersite inclusion. The occurrence of diamonds near a cavity lends apparently no support to the common belief that their presence in meteorites constitutes conclusive evidence of cooling under high pressure.