The area of the Grffin Lake garnet occurrence is underlain by high grade metamorphic rocks of the Precambrian-Paleozoic(?) Shuswap Metamorphic Complex consisting of gneisses and schists with interlayers of quartzite, marble and calcsilicate rocks. Narrow lenses of pegmatite occur along bedding planes and as dikes along joints and faults. Fine grained felsic to mafic dikes occur in northwest trending, late fractures.

Garnets occur in an alluvial fan just east of Griffin Lake. A comparitive investigation was made of the Griffin Lake garnets and those of the Emerald Creek commercial garnet deposit in Idaho (Beaty Geological Report, 1987 (located in Property File)).

The Griffin Lake or Revelstoke almandine garnets were considered to be comparable with the Emerald Creek garnets in almost every aspect except in their degree of fracturing and lack of euhedral crystals. This may be advantageous, however, as they may be capable of producing a sharper, more irregular and angular (ie, more abrasive) particle.