Group: Fossil specimens
Colors: Depends on the minerals that replaced the wood grain
Principal Sources: Worldwide
Special Notes: All the organic materials in the wood have been replaced with minerals (most often a silicate, such as quartz), while retaining the original structure of the wood (permineralization). The petrifaction process occurs underground, when wood becomes buried under sediment and is initially preserved due to a lack of oxygen. Mineral-laden water flowing through the sediment deposits minerals in the plant’s cells and as the plant’s ligning and cellulose decay, a stone mould forms in its place.