[meteorite-list] Mineral responsible for green color in Moldavite?

[MEM]

Sorry no such content.   Moldavites and Georgiasites are chemically very akin to 
soda glass, essentially identical to the sands they came from with a possible 
addition of iron from the impactor.  Nickel content is below detection 
thresholds, apparently.  Minor content of Na, K, Ca, Mg, Mn, Al and Ti--all 
typical of river sands.  With 3-4% Fe  one should think it was the iron but iron 
should make the glass more yellow if it were a silicate.   The valence of the 
iron +2 or +3 makes a difference in color.  There does not appear to be enough 
Mg to counter balance the iron...So other than knowing it isn't beryilium I 
don't know specifically, myself. Occums razor it must be the iron in combination 
with enough soda content.  


Chris I see why you offered a beryl guess but coloration , a general rule of 
thumb in mineralogy is that with rare exception "color" is the least reliable 
means to make an identification.  Remember the yellow and red "moldavites that 
were hitting ebay a few years ago?

Elton




----- Original Message ----
> From: Chris Spratt <cspratt at islandnet.com>
> To: meteorite-list at meteoritecentral.com
> Sent: Fri, December 10, 2010 1:15:49 PM
> Subject: Re: [meteorite-list] Mineral responsible for green color in 
Moldavite?
> 
> I think it may be a form of Beryilium or Beryl.
> 
> Chris. Spratt
> Victoria,  BC
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