Geology Question.....odd-Shaped Polyhedron

[Mosaic]

Ed, there's no geology section......
Has anyone ever come across the following: small 2cm across, shape is approximately a small stellated dodecahedron, dark brown, opaque, quite heavy for size.
It is allegedly natural not man made - sorry no photo.
The closest I can get to identifying it is the neolithic carved balls from Scotland, but they are not even very near in shape.
Imagine a very small caltrop and that's quite close.
Any identifications welcomed.

[wildwood]

Maybe it is a barb cluster from a barb-wire fence that has sprung loose.

[Mosaic]

Thanks wildwood - it is much 'meatier' than a barbed wire barb.

[Clanad]

Being, as you've described, a dodecahedron, especially a stellated example requires additional description to assist in identifying your mineral. Here in the western U.S. (according to my well worn, dog eared University of Wyoming Geology text) the most common example would be the pentagonal dodecahedron and is generally termed a pyritohedron, being most often found in the pyrites of the Rocky Mountain region. This could account for the color and heft of your example.

The other 3 examples of dodecahedron are rare, at least in our minerology. Yours is also described as "heavy"... pyrites are SG 5.0 (Average). The color you describe would fit some examples but not most...

[emeritus]

Google an Image of Whitmoreite is it anything like that ?

[Mosaic]

Thanks folks - pyritohedron has been suggested elsewhere. Definitely not whitmoreite though - much stubbier and not at all transluscent. I'm beginning to think maybe man-made....