[Rockhounds] Scapolite

[Axel Emmermann]

Hello Pete,

> Two new items to add, one is that I obtained a copy of the 1978 paper by
Pete J. Dunn (of
> Franklin-Sterling Hill, New Jersey, fame) + coauthors Nelen and
Norberg,?on "The
> Composition of Gem Scapolites", from Journal of Gemmology (the Brit's
spell it thus, with
> two m's), vol. 16, no. 1, pp. 4-10).? I'll just quote a bit from it here
that is especially
> interesting, and to those who would like?(Alex, etc.), I can email a copy
of the pdf file of the
> whole paper.? 

[Axel] 
Yes, please do Pete.

> "The most unusual scapolite the authors have seen was brought to their
attention by Mr.
> Herb Obodda, a noted American gem merchant.? This scapolite, reportedly
from Tanzania,
> has a very strong yellow body colour and the piece examined is facetable.?


[Axel] That sounds like my specimen.

The fluorescence
> of this material in ultraviolet radiation is remarkable for a gem
mineral.? The fluorescent
> colours are a strong yellow in short wavelength ultraviolet and an
extremely intense strong
> yellow in long wavelength ultraviolet.? 

[Axel] That doesn't ;-))) 


There is no phosphorescence.? ... This yellow gem
> material is a meionite, unlike the other Tanzanian gems examined, and has
a composition very
> close to the opaque Canadian material (#R13120), which has a similar if
somewhat less
> intense fluorescence."
[Axel] 
That sounds like Grenville materlial in gem quality.  

> and a second scapolite item of interest, a picture and description of a
purple, partially gemmy
> scapolite crystal from Afghanistan,?described as being meionite, is?shown
in Thomas P.
> Moore's "What's New in the Mineral World?" column in the?latest?issue of
the Mineralogical
> Record.??The column can be viewed online, it is posted at
> http://www.minrec.org/whatsnew.asp

[Axel] I looked at the photos. They are pretty. The colour strikes me like
being similar of that of amethyst. Could Fe3+ also be involved here?

Best regards
Axel