The Keystone-1 showing is located 5 kilometres north-northwest of Vernon, between Swan and Okanagan lakes.

In this area, west of the Okanagan Valley fault zone, volcanic and sedimentary rocks of the Devonian to Triassic Harper Ranch Group are unconformably overlain by Upper Triassic to Lower Jurassic Nicola Group sedimentary and volcanic rocks. These units are intruded by Middle Jurassic granitic rocks. Patches of Eocene Penticton Group volcanic rocks overlie the older rocks.

A quartz vein within tuffaceous volcanic rocks of the Nicola hosts copper mineralization. A malachite-stained vertical quartz vein, striking 095 degrees, carries minor chalcopyrite.

By 1931, an open cut had exposed the vein.