Fordite, also known as Detroit agate, comes in bright colors and psychedelic swirls, and are often crafted into eye-catching jewelry. But fordite is not a gemstone, rather it is dried paint that built up, layer upon layer, in factories that painted automobiles long ago. Especially in Detroit, and hence the name.

Before painting cars became an automated process, they were spray-painted by hand. Overspray in the painting bays gradually accumulated on the tracks and skids on which vehicles rested while they were painted. Over time, hundreds of layers of paint in myriad colors would build up in the ovens where the cars’ paint was hardened under high heat. Eventually, the build-up paint would become obstructing, or too thick and heavy, and had to be removed. No one can say for sure when the enamel paint slag left the plants, but possibly some crafty workers with an eye for beauty took them home and fashioned them into beautiful jewels.