African Petrified Wood Agate 6mm Round - 15-16 Inch #9189 The original stones were often

The original stones were often used as protective amulets and are usually scarred or pitted in places where they were ground off for use in traditional medicines

Opals are hydrated amorphous forms of silica

according to the Mohs hardness scale

that were deposited in shallow sea beds

African Petrified Wood Agate 6mm Round - 15-16 Inch #9189 The original stones were oftenPetrified Wood Agate is formed from the petrifaction process of primeval trees over the course of many years. Petrification occurs when the wood is covered by sedimentary rock, as waters loosen and decompose the organic elements and replace them with silicate substances, while maintaining the wood's original structure. Preservation is enabled by a lack of oxygen.