Concretions
Type of Rock:
SEDIMENTARY
RocksForKids.com
| Concretions are rounded rocks
embedded in layers of stone in sedimentary rocks. They are often harder
than the surrounding rock and weather out of the
host rock.
They are often spherical or nodules. Nodules are often shaped like
potatoes. Some concretions have unique appearances and are given special names. Some are:
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Concretions |
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 SPECIMEN ORIGIN: Eden, New York, USA |
 SPECIMEN ORIGIN: Rockwood, Michigan, USA |
 SPECIMEN ORIGIN: Yukon Territory, CANADA |
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 SPECIMEN LOCATION: Kettle Point, Ontario CANADA |
Cannon Balls -
Kettle Point, Ontario, CANADA This photo was taken at the Indian Reservation at Kettle Point, Ontario. The shale at the edge of Lake Huron is cracking and eroding away from the cannonball. The Point was named because the cannonballs appear like upside down cooking kettles coming through the shale. Many of the local people have dug up cannonballs from the lake and displayed them as ornaments on the front lawns of their homes. |
| Cannon Balls - NEW ZEALAND & AUSTRALIA | |
 Photos & description courtesy B. Daniels May 2003 |
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Photos were taken in
Central Australia, north of Alice Springs. Photos show the seashore in
southeast New Zealand (South Island). Many cannonballs are emerging and
rolling into the sea from the low bluffs to the left of the picture. Note that not all concretions are cannonball
shaped.
For more photos of cannon ball concretions, check out the following sites: |
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Septarian NodulesSeptarian nodules are common decorative stones that have been used making objects like bookends, clock faces, spheres, eggs or carvings. In North America, the most recognized septarian nodules come from Utah. |
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TurtlestonesTurtlestones are septarian nodules that look like the backs of turtles. The concretions are more oval in shape - like a turtle, rather than spherical - like a ball. The yellow calcite has "oozed out" between the grey rock material and looks like the markings on the back of a box turtle. |
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 SPECIMEN LOCATION: Eden, New York, USA |
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