Cobalt‐rich, nickel‐poor metal (wairauite) in the Ningqiang carbonaceous chondrite

Abstract

Abstract— A structurally ordered cubic metal grain containing ∼39 wt% Co, 61 wt% Fe, and <0.6 wt% Ni (∼Fe 3 Co 2 ) was found associated with troilite and pentlandite in the matrix of the Ningqiang carbonaceous chondrite. This mineral is similar to terrestrial wairauite. Experimental data in the Fe‐Co system indicate that this CsCl‐type Co‐rich metal is stable below 700 °C. Phase relations in the Fe‐Co‐Ni system show that Co cannot fractionate from Ni above 500 °C. The dominant opaque minerals of awaruite, magnetite, and pentlandite in Ningqiang suggest relatively oxidizing conditions.