Quartz diorite of the Mesozoic and/or Paleozoic Westcoast Complex is intruded by apophyses of quartz monzonite, possibly of the Lower to Middle Jurassic Island Plutonic Suite. The diorite outcrops are characterized by an abundance of metavolcanic and metasedimentary xenoliths. Discrete blocks of garnetite and epidote-garnet-diopside skarn occur within the intrusive rock.

The Tide showings occur near the southeast corner of Sprise Lake, near the intersection of two faults. The mineralization consists of fine to medium grained pyrite disseminations and stringers with lesser amounts of chalcopyrite, in diorite. About 1.25 kilometres to the north, minor pyrite and malachite stain occur as a fracture-filling in a quartz monzonite outcrop.