petrified wood

Polished slice of a petrified tree from the Late Triassic Period (approximately 230 million years ago) found in Arizona. The remains of insects can be detected in an enlarged image. Petrified log at the Petrified Forest National Park

Petrified wood is the name given to a special type of fossilized wood, the fossilized remains of terrestrial vegetation. Petrifaction (from Ancient Greek πέτρα meaning 'rock' or 'stone'), is the result of a tree or tree-like plants having been replaced by stone via a mineralization process that often includes permineralization and replacement. The organic materials making up cell walls have been replicated with minerals (mostly silica in the form of opal, chalcedony, or quartz). In some instances, the original structure of the stem tissue may be partially retained. Unlike other plant fossils, which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material.