GeologyRocksObject identification
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Without fotos it may be a
Sat, 02/06/2010 - 13:08Without fotos it may be a hard task. What exactly did you give your friend to have analysed? What are the %-values of each of the identified elements? Considering the elements I am under the impression that you had a bulk sample analysis, meaning you didnt have the mineral identified, but only got a element distribution of the entire sample including the dirt and silt on it. Jugding purely from the description of the object I would have guessed a marcasite or pyrite concretion, or similiar kind of concretions of iron-beairng minerals. Marcasite is common in clayey or carbonate bearing soils or sediments, however, the specific gravity would be much higher (at least 4,8 I think).
Perhaps an impure concretion of goethite or limonite could be the answer. But frankly, without some fotos and without a complete chemical results table we will not leave the realm of speculation here.
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I agree with the previous
Mon, 02/08/2010 - 13:27I agree with the previous post. Without a photo it's just speculation. My first thought was marcasite/pyrite or some other type of concretion such as flint, gypsum, calcite, etc, or even fossils such as echinoids (which might explain the "rods").
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Object identification
Submitted by vit on Fri, 02/05/2010 - 16:47.I apologise if I'm writing to the wrong forum, but I would be grateful if someone would help identify the objects I found some time ago or at least point me to where I can get help with this.
About 10-12 years ago, when I've been living in Russia, I was examining a heap of clay and silt raised while drilling a 10-metre deep water well. There was a lot of belemnites in silt, but besides these I have found some pretty interesting objects.
There were several spheres up to about 7 cm in diameter, several sphere segments of 60, 120 and 180 degrees, and some egg-shaped objects and broken "rods". All of them are made from the same mineral: uniformly black with uniform fine-dispersed composition with dull "sparkles", somewhat resembling cast iron. The surface, where it is not broken, looks fritted, resembling orange skin in texture and lustre. For sphere segments, only the "outer" curved surface looks fritted, while the sides look even and matte. Some segments have 1 or 2 concentric shallow "troughs" or "ridges" on their sides.
My freind had access to a laboratory, so he gave one of the samples for the analysis. The results I got were:
Composition: Si, Al, Mg, Ca, Na, Ba, Sr, Mn, P, Fe (Mg, Ca, Na are underlined, don't know what this means)Specific weight: 2.1 g/cm3Not conductive, light, composed mostly of oxides, low iron content.
I didn't pay too much attention to these objects after that and stored them away, but recalled them recently and would eventually like to find out what they are. I don't have any pictures at the moment and I'm currently living pretty far away from where these objects are, but I'll try to get them, if anyone is interested, it just might take some time.
Thank you.