A Picton artisan at Gwenyth Jewellery is turning old automotive spray paint from the General Motors Oshawa Assembly plant in Oshawa, Ontario, into colourful polished “gemstones.” The jeweller markets the pieces as GM-dite (also spelled GM-ite); they are made from layers of paint that built up on the factory’s interior racks, walls and equipment over many decades.
The material accumulated between the 1950s and the late 1980s, when car bodies and parts were hand-sprayed on racks and skids. Overspray built up on those metal fixtures and was repeatedly cured as the racks passed through the plant’s ovens, producing hard, multi-coloured strata.
Staff and historians at the Canadian Automotive Museum say these stones serve as a physical timeline of the plant’s work. Manual spraying was largely replaced in the 1980s by robotic electrostatic painting (an electrostatic process that produces almost no overspray), so this specific type of paint buildup is no longer being produced.
Much of the raw material was salvaged by former factory workers who took chunks home as souvenirs when older paint booths and fixtures were cleaned out. These rough pieces are now cut, shaped and polished with lapidary equipment into cabochons for necklaces and other accessories.
The finished jewellery is sold as a way for residents and collectors to wear a piece of Oshawa’s industrial heritage. Each stone reveals unique stripes and bands that correspond to the paint colours used on cars during the decades when the layers were deposited.
