Table made of petrified wood, the largest ever imported into the European Union.

Petrified wood, also referred to by the English term petrified wood, is a type of fossil: it consists of fossilized wood in which all organic materials have been replaced by minerals (usually silicates, such as quartz), while retaining the structure of the wood. The process of petrification occurs underground when a tree is buried under sediment, and it can take millions of years. Groundwater that slowly seeps through the soil deposits minerals where the lignin and cellulose decay. If the deposition and decay occur at the same rate, the shape of the cells is preserved. The smallest details can be immortalized. Fossilized annual rings and various tissues can be traced down to the microscopic level. Petrified wood is hardened to 7 on the Mohs hardness scale, the same as quartz. The petrification process has now been reduced to a few days in a laboratory. Petrified wood occurs in a wide spectrum of colors due to variations in the deposits of minerals such as manganese, iron, and copper. Quartz is colorless, but when iron is added, crystals with a red or yellow hue are formed, as shown in the list below: Carbon-black Cobalt: green/blue Chrome, green/blue Copper, green/blue Iron oxides—red, brown, yellow Manganese: pink/orange Manganese oxides—black Silica: white, gray. Locations: Argentina: The Petrified Forest National Monument in Santa Cruz, Argentina, is considered one of the world's best-preserved petrified forests; many petrified trees in Patagonia have a diameter of over 3 meters and are longer than 30 meters. Belgium: the geosite Goudberg near Hoegaarden *Greece: The Petrified Forest near Sigri on the western tip of the island of Lesbos is probably the largest petrified forest, over 150 km2. There are trunks up to 22 meters long. Large trees, complete with their roots, still stand upright there. Since 1985, it has been a protected natural monument. *Kerguelen: on the French islands, remains of petrified forests that are ninety million years old have been found.* *Namibia: The petrified trees near Khorixas were likely transported as tree trunks over rivers from the north to Namibia. Some recognizable trunks are 30 m long. *Austria: In the state of Carinthia, near Laas, there are remains of a petrified forest. Czech Republic: The largest stone is located in the Nová Paka museum village and is 8.20 m long. *United States: The largest specimens in the country reach about 1.8 m in diameter and are therefore significantly smaller than those in South America. A famous park is the Petrified Forest National Park in the state of Arizona.