The Phantom occurrence is underlain by a northwest trending pendant of metavolcanic and metasedimentary rocks of the Lower Cretaceous Gambier Group surrounded by quartz diorite and granodiorite of the Cenozoic-Mesozoic Coast Plutonic Complex.

Recent drilling on the Phantom property has revealed that bedrock comprises hornfelsed metasedimentary and metavolcanic rocks. Contact metamorphism has produced biotite hornfels containing minor small garnets, spotted andalusite-biotite hornfels and hornfelsed amygdaloidal andesite. The hornfelsed sediments and andesite contain minor to moderate amounts of pyrrhotite, pyrite and chalcopyrite. The sulphides occur as fine grained disseminations throughout the hornfelsed units, as blebs on fracture surfaces and in thin, infrequent quartz-carbonate veinlets. A drilling program in 1982 intersected a 1.5 metre section which assayed up to 0.6 grams per tonne gold (Assessment Report 17676). Scanning electron microscope (SEM) analysis of the spotted andalusite-biotite hornfels discovered rare-earth bearing phosphate, probably monazite, occurring as tiny grains 2 to 4 microns long, showing concentrations of yttrium, gadolinium and possibly dysprosium (Assessment Report 17676).