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Identity Helpuraninite?
22nd Feb 2012 16:05 UTCAnonymous User
It weighs 53,4 g
It is octahedral in structure
Streak is brownish - olive greenish
The voulme is difficult to estimate because the structure is not a perfect octahedron. Some peaces are missing on one side (maybee 35-25% of the overall volume of perfect octahedron). The sides are 23-26 mm long and by calculating the volume using a formula for octahedral voulme is:
without taking missing part into account ~8 cm3
Taking missing part (35-25%) into account ~5.2 -6 cm3
So density is >8 g/cm3 and <10.23 g/cm3
I am confused that it might be tantalite as that was the name I bought it under. The stone to the left in the streak picture is also supposed to be tantalite but this stone feels much less dense and has a dark brown-black streak (which fitts the description for tantalite better)
OK, I know you're going to say "test it for radioactivity" but I don't have a geigermeter laying around so what else can I do?
Thanks for any help!
/Lars
22nd Feb 2012 17:38 UTCErik Vercammen Expert
22nd Feb 2012 17:42 UTCReiner Mielke Expert
22nd Feb 2012 18:00 UTCMichael Wood
the crystal looks a bit too shiny for uraninite, which is usually dull, I think. But it does look rather like cassiterite, which is recorded from that part of the world, and cassiterite is quite dense. Just a thought.
Regards, Mike
22nd Feb 2012 18:03 UTCAnonymous User
22nd Feb 2012 19:46 UTCRonald John Gyllenhammer Expert
>"Is it impossible that it could be uraninte?"
It is possible for this to be Uraninite. You said it's greasy, heavy, brown green streak, octahedral, etc. These are all good indications. In the absence of radiation detection equiptment, you should measure the SG (specific gravity) more accurately. Use the method outlined above by Reiner. Also, check with a magnet to rule out Magnetite. Good luck with it.
Ron
22nd Feb 2012 21:48 UTCMatt Wall
Hope that helps, Matt.
:-)
22nd Feb 2012 22:03 UTCAnonymous User
I will take it with me to the lab I work in and do some density measurements. I'll also bring it to the isotope lab were we have some different kinds of geigermeters and check it there. That should defenately settle the matter, however.... Should this be uraninite.... is it valuable? How much could it catch?
24th Feb 2012 01:22 UTCPavel Kartashov Manager
I am suppose, that reaction of "tin mirror" will be positive in your case. ;)
24th Feb 2012 04:06 UTCRudy Bolona Expert
24th Feb 2012 09:35 UTCAndrew G. Christy Manager
24th Feb 2012 10:16 UTCAntónio Manuel Ináçio Martins
see: http://www.mindat.org/photo-43506.html
24th Feb 2012 22:06 UTCPavel Kartashov Manager
this crystal ABSOLUTELY isn't similar to any member of pyrochlore supergroup - crystallographicaly, by lustre, by colour, by streak. And it isn't uraninite of course.
29th Feb 2012 14:15 UTCRudy Bolona Expert
Have you been able to make any determinations on this crystal?
Rudy
1st Mar 2012 01:16 UTCCraig Mercer
1st Mar 2012 08:14 UTCMatt Wall
If that i pure Uraninite, then you should be getting up towards the $100 mark roughly, depending on the size. =)
5th Mar 2012 01:54 UTCHoward Heitner
12th Mar 2012 14:06 UTCAnonymous User
It has a SG of 7.053
It is not radioactive
It is not magnetic
My new best guess......Cassiterite
12th Mar 2012 14:19 UTCAlfredo Petrov Manager
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