The Armstrong Kyanite showing is located 6 kilometres east- northeast of Armstrong, on the ridge north of Glanzier Creek.

The area east of the Okanagan Valley fault is underlain by gneissic rocks of unknown age, metasedimentary rocks of the Proterozoic Silver Creek Formation, metasedimentary rocks of the Kootenay Assemblage including volcanic and sedimentary rocks of the Cambro- Ordovician Tsalkom Formation and the Upper Triassic to Lower Jurassic Nicola Group. All these units are probably in low-angle fault contact with each other. Middle Jurassic granitic plutons intrude these rocks. Mesozoic or Cenozoic pegmatite bodies intrude the Proterozoic Silver Creek Formation.

Mica schists of the Silver Creek Formation host abundant small kyanite crystals, formed during high grade metamorphism.