Jervis Island is underlain by sheared, fractured and locally schistose porphyritic volcanic rocks of the Upper Triassic Vancouver Group, Karmutsen Formation. Several steeply dipping shear zones striking 075 degrees contain lensy quartz veins up to 30 centimetres wide. The shears have been traced for over 100 metres and may also contain calcite, garnet and epidote.

The Jervis Island showing comprises lenses of chalcocite up to 15 centimetres wide and copper carbonates occurring in shear zones. A sample across a shear in a shallow shaft assayed trace gold, 6.8 grams per tonne silver and 4.7 per cent copper (Minister of Mines Annual Report 1926, page A320).