Petrified wood

Petrified wood (from the Latin root petro meaning "rock" or "stone"; literally "wood turned into stone") is the name given to a special type of fossilized remains of terrestrial vegetation. Petrifaction is the result of a tree or tree-like plants having been replaced by stone via a mineralization process that often includes permineralization and replacement.[1] The organic materials making up cell walls have been replicated with minerals (mostly a silicate, such as 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.

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

The petrifaction process occurs underground, when wood becomes buried in water-saturated sediment or volcanic ash. The presence of water reduces the availability of oxygen which inhibits aerobic decomposition by bacteria and fungi. 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. During replacement, the plant's cell walls act as a template for mineralization.[2] There needs to be a balance between the decay of cellulose and lignin and mineral templating for cellular detail to be preserved with fidelity. Most of the organic matter often decomposes, however some of the lignin may remain.[3] Silica in the form of Opal-A, can encrust and permeate wood relatively quickly in hot spring environments.[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.[5][6] A forest where such material has petrified becomes known as a petrified forest.


The outline of cells visible in a segment of petrified wood

Elements such as manganese, iron, and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Pure quartz crystals are colorless, but when contaminants are added to the process the crystals take on a yellow, red, or another tint.

Following is a list of contaminating elements and related color hues:[7][8]

Petrified wood can preserve the original structure of the stem in all its detail, down to the microscopic level. Structures such as tree rings and the various tissues are often observed features.

Petrified wood is a fossil in which the organic remains have been replaced by minerals in the slow process of being replaced with stone. This petrification process generally results in a quartz chalcedony mineralization. Special rare conditions must be met in order for the fallen stem to be transformed into fossil wood or petrified wood. In general, the fallen plants get buried in an environment free of oxygen (anaerobic environment), which preserves the original plant structure and general appearance. The other conditions include regular access to mineral-rich water in contact with the tissues, replacing the organic plant structure with inorganic minerals. The end result is petrified wood, a plant, with its original basic structure in place, replaced by stone.


Following the Great Depression in the 1930s, people began flocking to the mountains and deserts hoping to discover any sort of rock, stone or gem that could be turned into jewelry as a source of income. An assortment of rock was discovered which included petrified woods. "Rockhounding", as hobbyists would call it, became very popular. Many rock clubs began to establish throughout the United States. Soon after collectors started setting up rock shops where they were able to sell their merchandise to the public. As years went by rockhounders would perfect their craft at making jewelry using all sorts of different techniques, equipment, and molds. Having experience with their craft, first-generation rockhounders would soon teach fellow amateurs their skills.[9]


Areas with a large number of petrified trees include:


Chunk of petrified wood near El Kurru (Northern Sudan)
Petrified log and Welwitschia at Namibia Petrified forest




North AmericaEdit

Petrified logs at Petrified Forest National Park, Arizona, USA

South AmericaEdit

Petrified log in Paleorrota geopark, Brazil
Puyango petrified forest, Ecuador


See alsoEdit


  1. ^ Mustoe, George (2017-11-20). "Wood Petrifaction: A New View of Permineralization and Replacement". Geosciences. 7 (4): 17. doi:10.3390/geosciences7040119.
  2. ^ Leo, Richard; Barghoorn, Elso (1976-12-07). "Scilicification of Wood". Botanical Museum Leaflets, Harvard University. 25 (1): 47. JSTOR 41762773.
  3. ^ "Frequently Asked Questions - Petrified Forest National Park (U.S. National Park Service)".
  4. ^ Akahane, Hisatada; Furuno, Takeshi; Miyajima, Hiroshi; Yoshikawa, Toshiyuki; Yamamoto, Shigeru (2004-07-15). "Rapid wood silicification in hot spring water: An explanation of silicification of wood during the Earth's history". Sedimentary Geology. 169 (3–4): 219–228. Bibcode:2004SedG..169..219A. doi:10.1016/j.sedgeo.2004.06.003.
  5. ^ Muratal, Kiguma (1940-08-01). "Volcanic Ash as a Source of Silica for Silicification of Wood". American Journal of Science. 238: 10. doi:10.2475/ajs.238.8.586.
  6. ^ Matysovà, Petral; Roßler, Ronny; Götz, Jens; Leichmann, Jaromír; Forbes, Gordon; Taylor, Edith; Sakala, Jakub; Grygar, Tomáš (2010-06-01). "Alluvial and Volcanic Pathways to Silicified Plant Stems (Upper Carboniferous-Triassic) and their Taphonomic and Paleoenvironmental Meaning". Palaeogeography, Palaeoclimate, Palaeoecology. 292 (1–2): 17. doi:10.1016/j.palaeo.2010.03.036.
  7. ^ Mustoe, George (2016-05-01). "Origin of Petrified Wood Color". Geosciences. 6 (2): 25. Bibcode:2016Geosc...6...25M. doi:10.3390/geosciences6020025.
  8. ^ "What do the different colours mean in fossilized wood?". Fossil Design. Retrieved 2018-11-24.
  9. ^ Cross, Gary S. Cross. "Uses for Petrified Wood". OCLC 62165768. Cite journal requires |journal= (help)
  10. ^ "IAWA: The International Association of Wood Anatomists" (PDF).
  11. ^ "Petrified Wood Fossils from Madagascar".
  12. ^ Chunk of petrified wood near El Kurru (Northern Sudan) Retrieved 20 May 2019.
  13. ^ "Jurassic age plant fossil found near Dholavira". The Times of India. Retrieved 7 July 2014.
  15. ^ Jacob Leloux (May 25, 2001). "A petrified forest near Hoegaarden". Archived from the original on July 13, 2004.
  16. ^ The in situ Glyptostroboxylon forest of Hoegaarden (Belgium) at the Initial Eocene Thermal Maximum (55 Ma)M. Fairon-Demaret, E. Steurbaut, F. Damblon, C. Dupuis, T. Smith, P. Gerrienne (2003). "The in situ Glyptostroboxylon forest of Hoegaarden (Belgium) at the Initial Eocene Thermal Maximum (55 Ma)" (PDF). Review of Palaeobotany and Palynology. 126 (1–2): 103–129. doi:10.1016/S0034-6667(03)00062-9.CS1 maint: multiple names: authors list (link)
  17. ^ "Petrified Wood from Goudberg, Hoegaarden, Flemish Brabant Province, Belgium". Hudson Institute of Mineralogy. Retrieved May 14, 2016.
  18. ^ "Goderdzi Petrified Forest Natural Monument". Agency of Protected Areas of Georgia. Retrieved 11 September 2018.
  19. ^ Campbell, J.A.; Baxter M.S. (29 March 1979). "Radiocarbon measurements on submerged forest floating chronologies". Nature. Nature Publishing Group. 278 (5703): 409–413. Bibcode:1979Natur.278..409C. doi:10.1038/278409a0.
  20. ^ Stephencille Heritage site
  21. ^ "World's oldest fossil trees uncovered in New York". BBC. 19 December 2019.
  22. ^ "Unieke collectie van versteend houten producten". Retrieved 2 November 2016.
  23. ^ "RS VIRTUAL – O Rio Grande do Sul na Internet". Archived from the original on 2012-02-07.
  24. ^ FAPESP Research Magazine – Edition 210 – August 2013
  25. ^ Anon. "The Petrified Forest of Puyango". Viva travel guides. Viva. Retrieved 26 January 2010.

External linksEdit