Chromite formation was observed in experiments with a flash‐heating hemispherical‐implosion system, when a cylindrical steel sample holder, with stainless‐steel plug, containing a graphite/iron mixture was compressed by the implosion. The formation of chromite was observed and verified by x‐ray diffraction, scanning electron microscopy, and chemical microanalysis. The diffusion rates of Cr from the plug to the sample were as high as 102–103cm2s and growth rates of chromite crystals were as high as 0.3–0.4 ms−1. The foregoing could be inferred from the observations of the recovered specimens. Possible ways of chromite formation and the causes for the unusually high diffusion and crystal‐growth rates are discussed.