The Pike occurrence is located about 3 kilometres north of the mouth of Pike River on Atlin Lake, 23 kilometres south of the community of Atlin.

Argillites belonging to the Mississippian to Triassic Kedahda Formation of the Cache Creek Group Complex host a vein of white, compact, massive magnesite which contains about 10 per cent quartz. The vein is associated with an outcrop of upper Mississippian to Permian ultramafic rock of the Cache Creek Complex.