The Gnat 2 Fr. showing is situated on the eastern flank of the Lower Jurassic Guichon Creek batholith. The area is underlain primarily by Highland Valley phase medium-grained hornblende-biotite granodiorite intruded by Bethlehem phase dyke swarms. These rocks are highly fractured and altered.

Between Pete's Creek and Moly Creek, the granodiorite is intruded by quartz veins and pegmatite and aplite dykes varying in width from 2.5 centimetres to 30.5 metres. Potassium feldspar enrichment is evidently associated with the smaller intrusions. Widely spaced joints and tight fractures trend 020 degrees to 030 degrees. Mineralization occurs as thin coatings on fracture planes. The fractures are vertical and accompanied by barren conjugate sets trending 060 degrees.

The showing is located in the canyon of the eastern branch of Moly Creek where outcrop consists of aplite and microgranite. Small amounts of chalcopyrite and molybdenite are present.