The Apex mercury prospect is on the northeast slopes of Quartz Mountain and is accessible by a rough road from the nearby Poison Mountain road system. The Apex prospect is within carbonate and silica altered peridotite, serpentinite and greenstone of the Shulaps Ultramafic Complex. These rocks are now essentially listwanite and occupy an elongate zone up to 500 metres wide adjacent to the Yalakom fault. To the southwest, these rocks are in fault contact with greenstone and clastic sedimentary rocks of the Permo-Triassic Bridge River Complex, and to the northeast are in fault contact with middle Jurassic turbiditic sandstone and shale. Sills, dykes and plugs of augite diorite and plagioclase porphyry occur within the altered and unaltered serpentinite.

Cinnabar as fine veinlets, specks, blebs and lenses is in and along walls of grey translucent banded chalcedony which comprises part of the listwanite. The chalcedony contains some breccia fragments of ankeritized volcanic rock. Chalcedony veins either trend north and dip steeply, or strike 115 degrees and dip 35 degrees to 60 degrees to the south. Cinnabar also occurs, to a lesser extent, as disseminations throughout the listwanite and ankeritized greenstone. However, some areas of intensely listwanite-altered rocks contain only a trace of mercury. Foliated serpentinite and ankeritized volcanic rocks cut by diorite and porphyry contain only a trace of mercury. A sample of chalcedony breccia in listwanite containing cinnabar assayed 0.14 per cent mercury (Assessment Report 1916).

Approximately 1 kilometre to the northwest, a sample of listwanite from this belt of rocks contains traces of arsenic, antimony, mercury and gold (Open File 1988-9).