The Ruby Creek mica occurrence is located on Ruby (Lorimer?) Creek, approximately 74 kilometres north of the community of Germansen Landing.

Mica-bearing pegmatites, consisting of primarily feldspar and quartz, occur in an area underlain by mica schists, mafic gneisses and quartzites of the Neoproterozoic Ingenika Group. These rocks have been regionally metamorphosed to the kyanite zone of the amphibolite facies.

The mode of occurrence is described as similar to the Mica Mountain occurrence (094C 035) located 11 kilometres to the north (Minister of Mines Annual Report 1926, page 153) except that the metamorphic grade is higher, the rocks are more gneissic and pyrrhotite is abundant in the mafic layers. The pyrrhotite-rich bands are up to 6 metres in thickness. In 1930, a selected sample of pyrrhotite assayed trace gold and silver and nil nickel and copper (Minister of Mines Annual Report 1930, page A152).