The area of the Nuskarn showing is underlain by Upper Triassic sedimentary and volcanic rock of the Takla (Stuhini) Group. Lower to Middle Jurassic marine sedimentary and volcanic rock of the Hazelton Group occur to the immediate north. Devonian to Permian Asitka Group crystalline limestones are the oldest rocks exposed in the region. They are commonly in thrust contact with Upper Triassic Takla Group andesite flows and pyroclastic rocks.

Two prominent limestone bodies underlie the central and southcentral parts of the Breccia 4 claim, and extend a short distance into the Breccia 2 claim of Stealth Minerals in the mid-2000s. Skarn mineralization is associated with both lenses, although of only minor significance in association with the most southern body. The northern limestone body represents a lens, approaching 1 kilometre in length and up to 100 metres in thickness. It appears to wedge out to the north and possibly is faulted out to the south. Along its western margin, copper mineralization associated with quartz veins and epidote was noted to carry moderately anomalous silver and negligible gold. Intermittent mineralization was noted along the length of the eastern contact of the limestone. Here, northerly trending monzonite dikes were noted cutting the limestone in a few localities. Skarn minerals noted include magnetite, actinolite, garnet, calcite, epidote, chlorite, quartz, specularite and possibly ilvaite. Mineralization noted includes lenses, pods veins and proximal float of magnetite, magnetite-pyrite-chalcopyrite; calcite-actinolite-garnet-sphalerite-galena pyrite and pyrite-quartz chalcopyrite.

A sample taken in 2005 from a 20-metre pyritic skarn gossan assayed 12.8 per cent copper, 0.095 per cent lead, 4.25 per cent zinc, 90.5 grams per tonne silver and 0.3 gram per tonne gold (Assessment Report 20836).