GeologyRocksHello, and any suggestions regarding a small star dodecahedron thing....
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Hi, I doubt if it was a
Fri, 01/25/2013 - 00:07Hi,
I doubt if it was a meteorite , because generally they are shapeless because of being burnt up on entering the Earths atmosphere and this sounds very definite in shape.
You say its heavy (iron sort of weight) and a dodecahedron - my guess would be pyrite. It will rust to brown, and whilst it is considered a cubic mineral, it forms dodecahedrons frequently enough for them to be known as pyriteohedron.
They can also form into octohedra, and pyrite 'suns' - where they grow flat between bedding with crystals radiating outwards.
They also come as nodules generally round and when broken open, again the crystals are radial but come out in every direction. They are common here since they seem to form in chalk
The specific gravity/relative density would have been around 5 (precisely 5.2)
Does this help?
Has anyone else got ant other ideas?
John
“Civilisation exists by geological consent, subject to change without notice.” - Will Durant
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Cheers John!
Fri, 01/25/2013 - 09:32Like you I doubted the meteorite shtick, as the shape simply didn't fit with the object hurtling through the atmosphere and melting, then hitting the ground with a big thwack. Or thunk.
The student seems to have acquired it in the former eastern bloc, possibly Hungary, if that helps at all.
The nearest I have ever experienced to it are the 'Neolithic carved balls' found at Skara Brae etc - similar in sense of regularity and precision, but stellated and spikey rather than flat-sided.
I'm beginning to think this may be man-made - a mini-caltrop!
Thanks for your reply.
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I really don't know much
Sat, 01/26/2013 - 22:31I really don't know much about archaeology although I'd like to if I had time. So I Googled ' Neolithic Carved Balls'
It does say that they are mostly around 70 mm, and yours is 20 mm. However it says that some are carved from mafic minerals (these are a type of igneous rock such as dolerite etc) which have a higher than average SG/RD. But they are still not as heavy as pyrite, which is common and found worldwide. No reason for it not to come from Eastern Europe.
The stellated part you mention is generally found in calccite, which is comparatively very soft (about 4 on the Mohs Scale), and although it can be brownish, I've never heard/seen it rich dark brown. Neither would the SG/RD be abnormal. Probably the same as crustial rocks at around 2.7
Is it possible to get it back or get a photo of it?
John
“Civilisation exists by geological consent, subject to change without notice.” - Will Durant
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Hi Maggy. My initial
Fri, 02/01/2013 - 07:51Hi Maggy. My initial thought when reading your original post was the same as John's, ie a pyrite concretion. I believe there are quite extensive chalk deposits in Eastern Europe and that's the sort of rock you tend to get them in. Some of the smaller concretions are so symmetrical they can appear to be man-made.
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Hello, and any suggestions regarding a small star dodecahedron thing....
Submitted by Maggy on Thu, 01/24/2013 - 13:28.Hello folks
I wonder if anyone has ever come across a similar thing? Brought in by a student, about 2cm diameter, small star-shaped dodecahedron. Felt quite dense so maybe iron-rich, deep brown in colour. To my lasting shame did not photograph it. Student had been told it was a meteorite (?)
Any help will incur my lasting gratitude!
M