Chromian spinels have been observed as disseminated accessoriesin gabbroic rocks and ores from the abandoned Ni‐Cu mine of Kuså, in the Proterozoic metallogenic province of Bergslagen, Sweden. They occur as unzoned grains of “ferritchromit” (Fe0.92+Mg0.1Fe1.23+Cr0.6Al0.2O4), as two‐phase intergrowths composed of an Al‐rich phase (Fe0.52+Mg0.5Al1.4Cr0.4Fe0.23+O4) and “ferritchromit,” and as zoned grains with chromite cores (Fe0.82+Mg0.2Cr1.3Al0.4Fe0.33+O4) rimmed by “ferritchromit.” Betweent he core and the rim, two intermediate zones were observed: a light zone B (slightly depleted in Cr compared to the core) and a dark zone C enriched in Al (Fe0.82+Mg0.2Cr0.9Al0.6Fe0.53+O4) of all textural varieties are anomalously anisotropic. Chemical and textural observations on chromian spinels from Kuså suggest a miscibility gap along the magnetite‐chromite join between Mt40Chr60 and Mt70Chr30, and accordingly, a small correction to the previously described solvus is proposed.

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