The Spruce claim deposit consists of 2 breccia pipes, which are part of a larger series of breccia pipes extending along a six mile stretch of the Middle Fork of the Snoqualmie River. These breccia pipes intrude into the Snoqualmie batholith, and include the crystal producing deposits of Katie Belle, Pedro and Big Chief. The Spruce Claim breccia pipes are called Spruce and West Fault, and are exposed on a vertical cliff and cut by a fault. Quartz crystals are abundant in vugs at both outcrops. Associated minerals include ankerite, barite, bravoitite, calcite, chalcopyrite, chlorite, cosalite, epidote, galena, gold, malachite, pyrite, siderite and sphalerite.
Quartz crystals found in the West Fault are typically slender, and sometimes sceptred.
Quartz crystals in the Spruce are thicker and often associated with pyrite. In recent years the collecting has focused on the Spruce pipe, since West Fault has become buried by talis. The amethyst sceptre zone is part of the Spruce pipe, and was discovered above the main showing. Until this discovery, sceptre crystals were relatively uncommon in the Spruce pipe. This particular trip was an Explorers Group trip, which meant that the participants had to have been on 2 or more of Bob's trips in the past.