Fordite Art Deco 
Here we have a sweet Fordite round cabochon with Obsidian Black, Fire Red and Arctic White swirling colors in a fine silver setting and sterling silver double half round ring shank. 
Size 8
Fordite, also known as Detroit agate or Motor City agate, is a man-made material, not a naturally occurring gemstone.  It was formed from the buildup of layers of enamel paint overspray forming slag on tracks and skids on which cars were painted with acrylic lacquer, baked and hardened in paint booths and then chiseled off and polished. The unique material is a byproduct of the automotive industry, primarily from the mid-20th century when cars were painted by hand with multiple layers of paint.