The Black Prince occurrence area is underlain predominantly by Upper Triassic amygdaloidal basaltic rocks and locally interbedded limestone of the Karmutsen Formation (Vancouver Group) intruded by a quartz diorite stock. Garnet-epidote-magnetite skarns have been developed in siliceous volcanic rocks and limestone. Some marble has also been observed. Mineralization consists of massive magnetite with mixed chalcopyrite and pyrite carrying gold values. The magnetite is sometimes banded with pyrite and garnet.