You m y say you are petrified when you are too scared to move a muscle. ,The actual meaning of petrified is turned into stone and at such times this is just how you feel. When we speak of petrified wood, however, we are using the word in its strict meaning and a petrified forest is a whole forest of trees which has actually been turned into stone.
A piece of petrified wood may look for all the world like a log lying on the ground. But it does not feel like wood, for it is heavy and stony to'! , the touch. If you kick it, you will stub your toe. Actually, it is a perfect copy of a piece of wood, though it is made of stone through and through.
The stony specimen may be tinted with woodsy browns and greenish greys or it may be colored with vivid streaks of reds and golds. We need a microscope to prove it is indeed a perfect copy of woody tissue, cell by cell., Then we see the grain and the boxy cells arranged just as they are in living wood. The petrified wood was, in fact, once a living tree.
It lived and finally fell in some dry, sandy region where the rains were few and far between. For this reason it did not rot. In time it was buried by shifting sands and surrounded by seeping ground water. This water was loaded with dissolved chemicals stolen from various sandy rocks. It seeped into the woody tissues and bit by bit dissolved them also. But in place of them, the water left fragments of its chemicals which *time became stone.
The job of replacement took millions of years, for the stony copy of the on anal wood was built up molecule by molecule. The softer parts of the wood were dissolved and replaced first.
Ages later, the tough cell walls/were dissolved and replaced, but by this time the ground water often was carrying different chemicals.
The cell walls often were copied with minerals different from those used to copy the softer tissues and the beautiful designs can be seen enlarged under a microscope. The most common mineral in petrified wood is the silica which the ground water dissolved from the nearby sand, This hard, glossy mineral may be tinged with impurities and may take slightly different forms. Some petrified wood is agate, some is jasper. It may be semi precious opal, carnelian, onyx or chalcedony,
In North America there are several places where the earth has been working millions of years to turn an ancient forest into petrified wood. There are several petrified forests among the sandy deserts of Arizona. There are others in Texas and far to the north in Washington State near the Columbia river. These perfect copies of wood that once lived are usually made of durable and beautiful semi precious stones related to the quartz and silica minerals.