Fordite

Even though this is a man-made substance, it's so darn pretty that I couldn't help but share the link.

If you're a fan of color therapy, then boy has Fordite got some colors for you! Some of the specimens shown in the profile have a whole rainbow of hues in one "stone".

http://www.wire-sculpture.com/jewelr...utm_override=1

So if you see something made of Fordite, now you will know its origin. Despite its resemblance to an agate, it's man-made. This substance is actually turning into a collector's item, because the process of painting cars no longer creates waste or buildup of layers of paint.

So there you have it. A human-made substance that can be made into jewelry via the same lapidary techniques that are used on stones.