Slate was used to make a variety of tools, like this edge-ground knife. The initial preparation of the stone is rough abrasion to smooth and shape the overall form, then the edge (or edges) are finely ground or polished. Knives like this may have been used to cut and prepare fish for the drying racks.

This knife is from the Belcarra site, on British Columbia's coast, and is between 750 and 200 years old. Earlier examples of ground slate tools are found on other sites along the coast.