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Visitors are sometimes surprised when they see this famous forest.
You have to first picture the world of what is now Petrified Forest
Volcanic ash is often rich in silica.
Floods started to cover the tree with sediments.
Eventually mud, sand and volcanic ash covered the tree completely
Then the silica crystallized into quartz, replacing the wood cell by cell.
The process is not completely understood
In the end, tiny crystals less than one- two hundredth of a millimeter were formed.
Pure silica, though, is almost colorless.
As the rock layers bent and moved, some of the stone trees cracked and broke