The Shawn occurrence is hosted by argillaceous quartzites of the Lower Cambrian Reno Formation. The strata are intruded by granite to granodiorite of the Middle to Late Jurassic Nelson intrusions. Swarms of northeast-trending quartz veins with minor sulphides occur in the quartzites, including several which crosscut the stratigraphy at 320 degrees and at 040 to 050 degrees.

A quartz vein exposed in a trench near an old adit varied in widt from 5 to 15 centimetres and contained pyrite, chalcopyrite and galena. A grab sample of the vein assayed 6.84 grams per tonne gold, 25.0 grams per tonne silver and 0.6 per cent lead (Assessment Report 17233, page 18). Within a few hundred metres, other old trenches exposed veins. A grab sample from one such quartz vein graded 28.6 grams per tonne gold, 56.0 grams per tonne silver, 0.5 per cent lead and 0.024 per cent zinc; a 60 centimetre chip sample across this vein yielded 8 grams per tonne gold, 6.4 grams per tonne silver and minor amounts of lead and zinc (Assessment Report 17233, page 16).