A petrified forest is a forest made of fossilized or petrified wood. That is, it is a forest made of stone trees. Petrification is a natural process that occurs when all the organic matter in a tree dies and is replaced by a combination of quartz, copper, iron and other minerals. Once the process is complete, the petrified wood ceases to be considered wood and becomes a stone. In fact, petrified wood is the official stone of Washington. All petrified forests are national monuments and are carefully protected.
A petrified forest has been like this for millions of years. Some of the largest in the world are about 100 million years old. Volcanic ash is sometimes a key step in the petrification process. In fact, it is not uncommon for a petrified forest to have been covered in mud, which at one time was partly volcanic ash. Volcanic ash produces a chemical reaction in the wood, which in turn accelerates the petrification process.
A petrified forest can take on different colors, depending on the type of material once absorbed by living trees. Cobalt and copper cause a greenish blue hue, while manganese makes the wood pink and the carbon produces gray. Some trees have more than one color, while others are made mostly of crystalline quartz, which is transparent and allows you to see the grain of the wood.
The most impressive petrified forest in the world is located in Santa Cruz, Argentina. With trees over 10 meters in diameter, the petrified forest of Patagonia is one of the best examples of giant stone wood in the world. In comparison, the Petrified Forest National Park in northeastern Arizona, considered the best example of petrified wood in North America, is home to trees that reach barely six feet. Canada has the largest forest in the world, with an area of thousands of miles and dating back to the Eocene period.