These black druzy agate cabs are cut from a type of Brazilian agate called Umbu. This is the same variety of agate that produces the enhydro or water filled agates found in Brazil. This agate typically has only a gray color with muted banding. It is also very porous, which allows for the coloring process.

The agate is made black by a process known for centuries but perfected in Germany 100 years ago. It is first soaked in a concentrated sugar solution for several months and then boiled in sulfuric acid. The sugar molecules penetrate the porous agate and the sulfuric acid changes the sugar to carbon making the agate black. Our cabs are known for the juxtaposition of the shiny black agate against the tiny sparkle of the druzy quartz crystals. They are often set in gold with diamonds and other faceted stones.