You folks may be familiar with argillite as the stone that was used by Native Americans to carve trade goods for sailors after contact. I have never seen any reference to it being used as a bead material in British Columbia where the trade existed and apparently it was not used at all before contact. The argillite used for the trade goods was inferior to this grade and black shoe polish was used to give the pieces saturation and luster. Argillite however was used by the Salish tribes below the border to make pendants some of which are in the Burke Museum , Seattle. I imagine that they were created as an allusion to the ubiquitous traditional fishing net weights which were pierced with a substantial hole. I suspect this may be the best argillite in the world, very compact and saturated and enlivened with pyrite crystals.The source of this argillite was high in the mountains while the artifact pendants were made of a very common sea level argillite that can be found adjacent to many canoe pullout sites.