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Post by micahn on Apr 19, 2010 9:03:48 GMT -5
I have had this at least 30 years or so. I got it in Indiana and believe it is some sort of Geode. What makes it nice to me it the shape of it. Would finding one shaped like a star be rare ? Attachments:
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Post by lauriesrocks on Apr 19, 2010 9:54:53 GMT -5
It clearly looks like quartz, and is an obvious nodule. Whether it is a geode or not depends on whether it is hollow inside, with a cavity. If not it's just a nodule. Irregular shapes are not uncommon, not all geodes or nodules are round by any means, however yours does have a sort of star-like shape that is very unusual. It's very neat at any rate!
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Post by bammer on Apr 19, 2010 10:57:00 GMT -5
We collect geodes in IN often. Some are formed from ancient sponge fossils. If you turn it over it may have a cauliflower appearance and look a bit like a natural sponge. here are some we collected in IN.  they all look a bit like sponges. Some are hollow some are solid, most filled with quartz, some with calcite and other minerals. |
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Post by micahn on Apr 19, 2010 11:08:55 GMT -5
Thanks for the fast replies all.
Bammer yea I have also collected a bunch of them from Indiana. This one came out of a pile at my grand parents place. They used to have a lot by that I mean maybe 3 or 4 hundred of them that they collected over the years around. Next time I go up there will have to look around the pile again. They are older now so do not get out looking for things anymore (They are in their 90's)
We are from Green county Indiana (I live in Florida now) If I remember right we used to go a little south into the next county to collect them along a stream when I was a kid.
lauriesrocks I am sure this one is solid but I have others that are hollow.
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Post by micahn on Apr 19, 2010 11:13:32 GMT -5
Here is a couple more pictures of this one. Attachments:
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Post by micahn on Apr 19, 2010 11:15:05 GMT -5
And another Attachments:
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Post by scott on Apr 19, 2010 11:17:30 GMT -5
Hmm, must be a fossil or cast of something. Maybe an alien egg.
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Post by xtldggr on Apr 19, 2010 17:26:01 GMT -5
Micahn, That is a very neat specimen. The photographs you posted clearly display pentameral symmetry; a type of bilateral symmetry characterized by the repitition of morphological features in multiples of five. This type of symmetry is only present in fossils of the phyllum Echinodermata. Your specimen is quite likely the calyx of a crinoid. Very cool indeed!! Below is a photo of a specimen of a geodized crinoid from Indiana; as you can see they are almost identical. John-xtldggr-Makohon  |
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Post by elementary on May 2, 2010 19:02:37 GMT -5
Check out the book _Geodes, Nature's Treasures_ by Brad Cross and June Zeitner.
Chapter nine is called "Strange Geodes of Indiana" and discusses how fossils there transformed to geodes. During this process they expanded forming amazing shapes that are very similar to yours. There's 5 or 6 photos that show examples of this type of geode.
To to follow up on the prior post, I'm pretty sure that is what you have here.
Lowell
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