2. The mystery
object is
PETRIFIED
WOOD
from Arizona.
3. Petrified wood is a
special type of
fossil. It has the
tree’s original
shape and
structure, but the
living material has
been replaced by
minerals and
stone.
4. Our specimen began
forming millions of
years ago when logs
washed into an
ancient river or sea.
The logs were buried
by great amounts of
sediment, but because there was very
little oxygen, the logs did not decay
normally.
5. The log broke down
very slowly over
hundreds of years.
Minerals absorbed
into the wood. The
minerals replaced
pieces of the wood
as it decayed.
6. Our particular specimen
is sometimes called
“rainbow” petrified
wood because of its
many colors. It is made
of almost solid quartz.
Quartz is usually clear,
but when elements are
in the water/mud during
the petrification, other
colors are produced.
7. Here is a list of elements
and the colors they may
produce in the petrified
wood:
• carbon - black
• cobalt - green/blue
• chromium - green/blue
• copper - green/blue
• iron oxides - red, brown,
and yellow
• manganese - pink/orange
• manganese oxides -
black/yellow
8. Petrified Forest National Park in the
Painted Desert of Arizona contains one
of the world’s largest and most colorful
areas of petrified wood.
