Petrography and mineral chemistry of Ca, Al-rich inclusions of Ningqiang ca
rbonaceous chondrite are studied and the highly Re-Os fractionated Pt-metal
nuggets in it is discovered. The refractory inclusions are classified into
melilite-spinel-rich, and spinel-pyroxene-rich types. The former probably
crystallized from melts, while the latter could be aggregates of the nebula
r condensates. The strong fractionation between Re and Os suggests a pre-so
lar origin of the Pt-metal nuggets, which probably experienced various proc
esses of formation and evolution before being captured by the refractory in
clusions as indicated by the depletions of W and Mo.