Petrified wood tumbled stones
How does petrified wood originate?
Petrified wood, or fossil wood, is a stone that originates from trees that have ended up under thick layers of volcanic ash. The ash contains all kinds of minerals, which slowly dissolve in the groundwater. Because the trees are no longer in contact with oxygen, the wood does not rot as fast as normal. In the meantime, the groundwater permeates the tree with minerals where they settle in the wood cells. Slowly but surely the wood decays and the minerals take the place of the wood cells. This happens very slowly so that the structure of the wood is perfectly preserved in the minerals.
220 million years old
Petrified wood therefore no longer contains real wood, but only the imprint of the tree formed by minerals. These pieces from Madagascar are 220 million years old and are filled with richly coloured minerals.