Petrified wood
Encyclopedia : P : PE : PET : Petrified wood
Petrified wood is a type of fossil: it exists of fossil wood where all the organic materials have been replaced with minerals (most often a silicate, such as quartz), while retaining the original structure of the wood. The petrifaction process has occurred underground, when wood became buried under sediment. Mineral-rich water flowing through the sediment deposited minerals in the plant's cells and as the plant's lignin and cellulose decayed away, a stone cast was formed in its place.
Minerals such as manganese, iron, and copper in the water/mud during the petrification process give petrified wood a variety of color ranges. Quartz crystals are colorless, but when iron is added to the process the crystals become stained with a yellow or red tint.
Following is a list of minerals and related color hues:
- carbon - black
- cobalt - green/blue
- chromium - green/blue
- copper - green/blue
- iron oxides - red, brown, yellow
- manganese - pink/orange
- manganese oxides - black
- silica - white, grey
Petrified wood has a Mohs hardness level of 7, the same as quartz. Materials scientists have been able to make artificial petrified wood recently [link].
Petrified wood is also the state gem of Washington.
Locations
- Argentina. Considered to be one of the world's best petrified reserves, the Petrified Forest National Monument in Santa Cruz, the Argentine Patagonia has many trees that measure more than 3 m (10 ft) in diameter and 30 m (100 ft) long. Compared to petrified trees in the United States that measure less than 1.8 m (6 ft) in diameter, the trees of the Central Steppes of Argentina are significantly larger.
- Czech Republic, Nová Paka. The most famous locality on Permian-Carboniferous rocks in the Czech Republic.
- Greece. Petrified Forest of Lesvos, at the western tip of the island of Lesbos is possibly the largest of the petrified forests, covering an area of over 150 km² and declared a National Monument in 1985. Large, upright trunks complete with root systems can be found, as well as trunks up to 22 m in length.
- United States. A famous petrified wood site is Petrified Forest National Park in the U.S. state of Arizona. Wood from the area (though not from the park) is a prized commercial item, particularly cut and polished samples.
See also
External links
From Wikipedia, the Free Encyclopedia. Original article here. Support Wikipedia by contributing or donating.
All text is available under the terms of the GNU Free Documentation License See Wikipedia Copyrights for details.