Mixed Dark Lepidocrocite 8mm Large Hole Round - 8 Inch 6-8X10-12mm Agate is one of many

Agate is one of many varieties of banded Chalcedony

It is a very soft stone typically found near copper deposits

air bubbles or black carbon deposits

siderophyllite

depositing copper and other elements that gradually develop into turquoise

Mixed Dark Lepidocrocite 8mm Large Hole Round - 8 Inch 6-8X10-12mm Agate is one of manyAn iron oxide hydroxide mineral, Lepidocrocite forms when iron containing substances rust underwater. It is commonly found in the weathering of primary iron minerals and in iron ore deposits, and can be red to reddish brown. When skillfully cut and polished, those substances add a delicate accent to the otherwise clear gemstone.