Banded Onyx is the result of slow, cold water precipitation of calcite saturated with iron oxidized (red) or reduced (green) crystals. It comes from a single location near the border of Pakistan with Iran. It is mined in solid stone blocks that are then turned on lathes by artisans to create these beautiful bowls and other home accessories. Use care to protect the polished finish. Not recommended for use in dishwasher or microwave. Acidic foods will dull the polish over time.