Coarse-grained... | [ Sizes: Orig | Large | Med | Small | Thumb ] |
In WS part of "Staroscinskie Skaly" I observed coarse-grained granite covered probably by black mineral called goethite.
Comments
[ Post a Comment ]| Dan Dalton | Huh... | | 
Hasn't voted | you stumped me, I have never heard of this mineral before. I am going to have to go and do some research!
Dan | | Posted Jul 25, 2007 1:24 pm |
 | | Romuald Kosina | Re: Huh... | | 
Hasn't voted | MMDan, do not affraid so much!!!! :-))))))
I wrote "probably". This granite has a little inside a powder of limonite with good green fluorescence. There is possibility to create a layer of psylomelan, however, I also must check it with some help of my friends, mineralogists. Now I know that this black layer is of mineral origin, not from fire or pollution.
Nice to hear you again!!!!!!
Cheers!!!!!
Romek | | Posted Jul 25, 2007 1:34 pm |
| | Romuald Kosina | Re: Huh... | |
Hasn't voted | Hi, MMDan!!!
I looked at this mineral under microscope, also on pieces of rocks from another mountain in Rudawy (Wielka Kopa) and, provisionally, I can change this determination, rather it is not psylomelan, there are visible good transmissions between hematite and goethite like pseudomorphosis.
Of course it will be more studied, maybe by X-rays analysis.
Cheers !!!
Romek | | Posted Jul 26, 2007 2:00 pm |
| | Dan Dalton | Re: Huh... | |
Hasn't voted | Right on! This is turning to be a quite interesting mineral identification. I have always had a hared time in thin section or under the scope identifying less common minerals. If you get the chance, x-ray difraction will be able to tell exactly the chemical make-up and what mineral it is. Keep me posted!
Dan | | Posted Jul 26, 2007 2:32 pm |
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