The Mount Prince northwest showing occurs in an area underlain by Upper Triassic Takla Group volcanic rocks. The Takla Group, to the west, is in fault contact with mainly Paleozoic rocks equivalent to the Cache Creek Group. The fault separating the two groups of rocks is the Pinchi Fault, a major structural feature marking the boundary of the Cache Creek and Quesnellia terranes. Adjacent to the fault within Takla Group rocks are a number of mercury occurrences of which some have, in the past, been worked.

The Mount Prince northwest showing consists of small amounts of cinnabar in carbonatized and sheared mafic volcanics of the Takla Group. The cinnabar commonly occurs within quartz stringers.