[Rockhounds] Scapolite

[Axel Emmermann]

Hi Nate; 

You'll find crystals of both minerals probably.
What I meant to say was: are large good quality crystals of marialite more
abundant than those of meionite (or in general, is the formation of these
crystals more likely towards the sodium, chlorine-rich part of the series).

Axel

> -----Oorspronkelijk bericht-----
> Van: rockhounds-bounces at lists.drizzle.com
[mailto:rockhounds-bounces at lists.drizzle.com]
> Namens Nathan Martin
> Verzonden: maandag 22 september 2008 15:13
> Aan: Rockhounds at drizzle.com: A mailing list for rock and gem collectors
> Onderwerp: Re: [Rockhounds] Scapolite
> 
> Axel,
> What is your criterion for large crystals?
> 
> The classic Webster vesuvianite prospect in Sanford, ME is reputed to
> provide meionite crystals (see the Mineralogical Record, Volume 24, No. 5
> and Mineralogy of Maine by King and Foord).  I have self-collected
crystals
> that appear to be meionite that are in the 5/8" range and Peter Cristofono
> has a photo on mindat from this locality of a 4 cm specimen.
> 
> best regards,
> Nate Martin
> Lexington, MA
> 
> 
> On Sun, Sep 21, 2008 at 6:11 PM, Axel Emmermann
> <axel.emmermann at pandora.be>wrote:
> 
> > Hi list,
> >
> > I'm doing some pondering on scapolite.
> >
> > Does anybody know whether the Ca and CO3-rich end-member, meionite, is
less
> > likely to be found well formed, large crystals than the Na and Cl
> > end-member
> > marialite?
> >
> > It should have something to do with crystal-chemical hindering by the
> > carbonate group sticking through one of the boundary planes of the unit
> > cell.
> >
> > Anybody who knows?
> >
> > Cheers
> >
> > Axel
> >
> 
> 
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