THE FORMATION OF AGATES

    To me, one of the most beautiful of the pebbles commonly found in the stream
beds and gravel pits of Iowa is the banded agate. The mineralogist says it is a form of the
mineral he calls chalcedony {kal-ked'-ony}; the chemist calls it silicon dioxide and says it
is merely another form of quartz, or common sand; the jeweler classifies it as a
semi-precious gem and uses it is rings, pins, and cameos. Since we are not mineralogists,
chemists, or jewelers what does the agate mean to us? To those of us who have never
hiked up stream beds, played in the sand and gravel, or splashed around in creeks while on
a picnic the agate has no meaning. Those of us who have been fortunate enough to bruise
our feet upon the pebbles of the stream bed, and build castles in the sand will remember
with pleasure those gorgeous striped pebbles with their varied shadings of red, grey, and
white, and their satiny waxen lustre. Why, even yet I can remember the first agate I found.

    The agate has more interest for me, though, than its fascinating beauty. The story
of the growth of the agate is also of enthralling interest; in fact it reads like the fairy tales
of our childhood days. It even starts like those olden tales. Once upon a time, long years
ago; even before the distant days of the ice age, mighty conflicts raged within the earth and
often hot molten lava burst its way through to the surface. Bubbles of gas collected all
through this molten rock and made the lava, upon solidification, very porous. In this way
was the trundle bed prepared for the princess of our fairy tale, the agate. Years passed and
water began finding its way through the lava. This water carried with it in solution, tiny
amounts of quartz, that mineral which makes up the most of our sand. Also in solution
was varied amounts of iron, manganese, and other substances to give color to the embryo
agate. Through hundreds of years water seeped through the lava and, as it passed slowly
through the cavities, deposited layer upon layer of the mineral it had carried in solution.
Some times the layer was clean and red because of the iron coloring; sometimes grey due
to the presence of the manganese. At other times the band deposited was dull and had lost
its transparency. Then again, but rarely, the center, after a number of bands had been
deposited was filled in with crystals.

    Countless other years passed and the lava became broken and weather worn. Then
the earth became cold and ice covered a great portion of our temperate zone. The great
sheets of ice formed in Canada and flowed, or slid southward. From various places along
the way the ice picked up and carried with it huge chunks of rock. A number of these ice
sheets reached south only into Iowa; and, as they melted back, they deposited their loads
of rock. Somewhere along their route these glaciers collected the weather-worn lava; so
among the debris of rock left in Iowa by the ice was this lava containing the banded
agates. More weathering took place and finally the agates fell loose from the mother rock;
but you would have never taken them for beautiful gems, for the surface was dull, drab,
and very roughly pitted. In the course of a rough and tumble existence in a rock strewn
stream bed some of these uninteresting little stones became broken. Others waited for
some inquisitive person's blow with rock or hammer to disclose their true beauty.

    Now that you know the story of the formation of this pretty little stone, why not
spend some Sunday afternoon exploring the mysteries of a pebbly creek bottom? When
you find an agate you might ponder over the fact that some great force in the universe sees
fit to make things of beauty from the most unlikely of conditions and circumstances. Had
you before considered that an object of beauty such as an agate could result from such a
barren, ugly spot as a lava bed?

Dorris Willows
Nov. 22, 1933
English 1-10
Theme No. 6

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