Fordite, also known as Detroit agate, is actually old automobile paint which has hardened sufficiently to be cut and polished. It was formed from the build up of layers of enamel paint slag on tracks and skids on which cars were hand spray-painted (a now automated process), which have been baked numerous times. In recent times the material has been recycled as eco-friendly jewelry.
10 Most Rare Gemstones in the World Rarer than a Diamond | Geology IN
Russian Sphene 14.50ct. Titanite (Sphene). The mineralogical name Titanite comes from its titanium contents. Sphene is a very rare brilliant yellowish-green, green, orange or brown gemstone with a high lustre.
The roman Senator, Nonius, owned a beautiful opal that Mark Anthony so wanted to buy as a gift for Cleopatra. Under the threat of death to sell, he preferred to exile rather tan part with his precious gem.