Petrified Wood 45

Petrified wood is the result of a tree which has completely been transitioned to stone by the process of permineralization. All the organic materials (i.e. wood) have been replaced with minerals (mostly a silicate, such as quartz), while retaining the original structure of the stem tissue. Therefore petrified wood is a three-dimensional representation of the original organic material. The petrifaction process occurs underground, when wood becomes burried under sediment and is initially preserved due to a lack of oxygen which inhibits aerobic decomposition. Mineral-laden water flowing through the sediment deposits minerals in the plant's cells; as the plant's lignin and cellulose decay, a stone mould forms in its place. Petrified wood is 6 to 20 million years old.