It takes a full day working in temperatures up to 1,000 degrees Celsius to make one batch of Himalayan black salt, or kala namak. The salt was once used as a medicine to treat indigestion.
In Uruguay, Renato sets off an explosive to reveal an ancient, glittery stone: amethyst. In Italy, Enrico cuts slabs off of one of the most expensive marbles in the world: Calacatta.
Fleur de sel is a rare, unrefined salt that is made by evaporating seawater slowly in 2-centimeter-deep ponds. It's made in western France using centuries-old methods. Just locally, it can cost 230 times more than table salt. Outside French borders, it can reach $420 per kilogram.