Petrified wood

[1] The organic materials making up cell walls have been replicated with minerals (mostly silica in the form of opal, chalcedony, or quartz).

Unlike other plant fossils, which are typically impressions or compressions, petrified wood is a three-dimensional representation of the original organic material.

Mineral-laden water flowing through the sediments may lead to permineralization, which occurs when minerals precipitate out of solution filling the interiors of cells and other empty spaces.

[4] However, petrified wood is most commonly associated with trees that were buried in fine grained sediments of deltas and floodplains or volcanic lahars and ash beds.

Petrified wood forms when woody stems of plants are buried in wet sediments saturated with dissolved minerals.

Cellulose is composed of long chains of polymerized glucose arranged into microfibrils that reinforce the cell walls in the wood.

In addition to microbial decomposition, wood buried in an alkaline environment is rapidly broken down by inorganic reactions with the alkali.

[2][1] The remaining material is nearly pure silica, with only iron, aluminum, and alkali and alkaline earth elements present in more than trace amounts.

These Lagerstätte deposits include the Paleozoic Rhynie Chert and East Kirkton Limestone beds, which record early stages in the evolution of land plants.

Boron, zinc, and phosphorus are anomalously low in fossil wood, suggesting they are leached away or scavenged by microorganisms.

[2] Petrified wood has limited use in jewelry, but is mostly used for decorative pieces such as book ends, table tops, clock faces, or other ornamental objects.

[18][19] Petrified wood is found worldwide in sedimentary beds ranging in age from the Devonian (about 390 million years ago), when woody plants first appeared on dry land, to nearly the present.

Petrified "forests" tend to be either entire ecosystems buried by volcanic eruptions, in which trunks often remain in their growth positions, or accumulations of drift wood in fluvial environments.

[5] Petrified wood can also form in arkosic sediments, rich in feldspar and other minerals that release silica as they break down.

Polished slice of a petrified tree from the Late Triassic Epoch (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
Microscopic view of petrified Callixylon wood
Petrified wood mineralized with carnotite from St. George, Utah
Petrified wood from the Shinarump Formation at the Nacimiento Mine, Cuba, New Mexico. The brown wood at right shows conventional silica mineralization. The black wood at left shows unusual mineralization with chalcocite and other sulfide minerals. The blue-green stains are from oxidation of the chalcocite to azurite and malachite.
Table constructed from petrified wood
Chunk of petrified wood near El Kurru (Northern Sudan)
Petrified log and Welwitschia at Namibia Petrified forest
Petrified logs at Petrified Forest National Park, Arizona, USA
Petrified log in Paleorrota geopark, Brazil
Puyango petrified forest, Ecuador