C. approximately 220 million years – Triassic period A well preserved and polished petrified fossil wood slice. Petrification of wood is the name given to a special type of fossilized remains of terrestrial vegetation. It is the process of permineralization which involves a tree having turned completely into stone. Petrification of wood invoices minerals (usually silica or calcium carbonate) being absorbed into the wood, replacing the all organic materials, while retaining the original structure of the wood. This process occurs when the wood is buried under sediment, and is preserved due to a lack of oxygen. The minerals in the water, flowing through the sediment are absorbed into the plant’s cells, so as the cellulose and lignin decompose, a stone mold is formed in its place. Nice example with strong colours and a decorative piece. Stand included. Size: D: 11mm x W: 110mm x L: 156mm approx