Peridot is the name for the gem variety of the mineral "olivine". It has been found at several sites in Britsh Columbia all associated with fairly young (geologically speaking) basaltic volcanic rocks. Rough peridot occurs within nodules in the basalt. Interestingly, these nodules are believed to be pieces of the upper mantle, the layer of the earth beneath the crust, which have been carried to the surface by the basaltic lava. Learn more here and here.
The peridot offered for sale here comes from several localities in British Columbia, including Lightning Peak, near Cherryville and near Lumby. Learn more about Canadian peridot on page 24 here