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| Petrified birch from the Blue Forest, Wyoming. |
In my spiritual life, to better
connect to the natural world around me, I use allies as focusing tools, like
animals, plants, and stones. I love trees, and feel a strong affinity with
them. They have taught me to slow down, to stand and be present in the moment,
to breathe in seasons and touch stillness. For this same reason, one of my
favorite stones to work with is petrified wood. I use a lot of fossils, the
petrified remains of organics that lived millions of years ago. I call them earth
bones. They are the ancestral stones I hold when I meditate backwards through
my family lines.
Almost as magical as the rock
itself, is the process it undergoes to become stone. The word petro is Greek for
“rock/stone.” When something petrifies, it literally becomes stone in a
process called permineralization, where organic
material is replaced over time with minerals, mostly silicates. Many fossils
form as compressions or impressions, but petrified wood uniquely forms as a
three-dimensional representation of the original, preserving detail at the
microscopic level. To feel the weight of the minerals in your hand and the
coolness of the stone while your eyes perceive grainy bark… it is a wonder of
the natural world.
Wood
becomes preserved when it is buried under sediment, where a lack of oxygen
stops aerobic decomposition. Then, water rich in minerals flows through the
sediment, where they deposit in the plant cells. Permineralization
begins when silica from the mineral-laden water permeates the wood. Next, this
solution penetrates the pores of the cell walls. Then the cell walls,
cellulose, begin to dissolve while, elsewhere in the trunk, the minerals begin
to build up, preserving the wooden frame. The last to decay is the inner lignin
of the tree. Afterwards, silica deposits itself in any spaces in between the
cells, until it finally penetrates the cell lumina, the cavity within the walls
of the plant cell. It might fill these voids with chalcedony, agate, quartz,
calcite, pyrite, or opal. Finally, lithification occurs, which is the process where
sediment compresses under pressure, into rock, as water loss continues to occur.
The initial silica is amorphous, which is
unstable. Over millions of years, due to more extensive polymerization and
water loss, the silica transforms into a more stable crystalline structure,
like opal or quartz.
Cellulose, hemicelluloses, and lignin account for 95%
of the dry weight of live wood. After permineralization, 90% of the weight of
the fossil is silica, showing that very little, if any, of the original
material remains [according to Leo & Barghoorn (1976), Sigleo (1978), and
Mustoe(2008)]. Permineralization is one
of the most accurate modes of fossil preservation. Because different layers of
the wood decay and fill in with silicates at differing rates, it preserves the
individual parts of the tree, though accuracy varies between specimens. Some
are “sugary,” where the cell detail is blurred. Others show the tree rings
intact, and still more are comprised of such a fine grain of silica, that the
histology of the original tree can be studied satisfactorily.
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| Believe it or not, that bark is pure stone! |
Some
specimens of petrified wood, when uncovered, are pure silicate/quartz white,
though, over time the sun will darken it. Other minerals add to the beautiful
colors of the petrified wood. Carbon colors the specimen black. Cobalt and
chromium both add hues of green and blue. Manganese tinges the stone with pink
and orange, while manganese oxides color it in yellow and black. Iron oxides
color it with red, brown, and yellow.
Petrified wood is a common fossil,
but the conditions needed to create it are specific. Temperatures over 212 degrees
Fahrenheit will break the wood down before the process can occur and excessive
pressures will deform the organic tissues. And not only does it need
mineral-rich water but, chemically, wood breaks down when the water’s pH value
is below 4.5 and above 7, so the window for a perfect environment is still precise.
They are treasure from the earth,
gifts in their assurance as to the cyclical nature of life, and the knowledge
that life will out in the end. I use them as touchstones. Their process of
transformation traverses so many millions of years that I use them to connect
to the past, as if I can take a shortcut and touch any point of time in their
linear history. When you come across petrified wood, take a moment to touch it
and connect into it. Touch the energy of the spirit of the tree it was once a
part of and be reminded of the larger, universal web we are all a part of.
Facts and Folklore
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Most of the petrified trees have been given the
name Araucarioxylon
arizonicum.
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Petrified wood is found on every continent
except for Antarctica.
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There are petrified trees more than 10 feet in
diameter and 100 feet long at the Petrified Forest National Monument, Santa Cruz Province, Argentine Patagonia.
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The stone of Alberta, Canada is petrified wood.
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The Chinese government has cracked down on the collecting of this
material.
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The Museum of Natural History in Chemnitz, Germany has specimens that date back to their discovery in 1737.
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The Puyango Petrified Forest in Ecuador has one
of the largest collections in the world.
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Egypt declared their petrified forests to be national
protectorates.
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The largest forest can be found in the Petrified
Forest of Lesvos, on Lesbos, Greece, covering 93 miles. Upright trunks with
roots intact can be found there. Some trunks measure up to 72 feet in length.
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In the Great Sand Sea of Libya, pieces of
petrified trunks and branches are littered over hundreds of square miles, along
with Stone Age artifacts.
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At low tide along the coast of Wales and
England, submerged petrified forests become visible.
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Seven species of tree have been identified
through petrified wood.
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Petrified wood is often used in lapidary work,
cut into cabochons for jewelry and slabs for table tops and counters.
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The oldest known species of petrified wood can
be found near Gilboa, New York, dating to the Devonian period, over 358 million
years old.
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The stone in the National park in Arizona are of
the Triassic Period, over 160 million years old.
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Petrified wood is associated in metaphysical
worlds with the astrological sign Leo and the Base Chakra.
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Petrified wood
and dinosaur bones are the best-known specimens of permineralized fossils.
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Petrified wood is found in large numbers in
Argentina, Australia, Belgium, Brazil, Canada, China, the Czech Republic,
Germany, Ecuador, Egypt, France, Greece, Indonesia, India, Israel, Libya,
Namibia, New Zealand, Saudi Arabia, Thailand, Ukraine, United Kingdom, and the
United States.
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In the United States, Petrified Forests and
Parks can be found in abundance: the Gilboa Fossil Forest in New York; the Petrified
Forest in Mississippi; the park in Lemmon, South Dakota; Theodore Roosevelt
National Park in North Dakota; the Petrified Springs in Kenosha, Wisconsin;
Yellowstone Petrified Forest and Gallatin Petrified Forest in Yellowstone,
Wyoming; the Florissant Fossil Beds National Monument in Colorado; the Ginkgo
Petrified Forest, Wanapum State Park in Washington; the forest in Calistoga,
California; the National Park in Holbrook, Arizona; the Escalante Petrified
Forest State Park in Utah.
