Zircophyllite - Água de Pau volcano, San Miguel Island, Azores District, Portugal

Something strange going on with this photo.

It's a POTD but it doesn't show up in the zircophyllite gallery, nor in the locality gallery

That's because the identity has been questioned; might not have quite enough zirconium to be that species.

Hi,
and (Ti+Zr) ?
A Ti rich zircophyllite...

Cheers,
Pedro

Hi Pedro,
analysis (by Roma University) are current...
Ciao. Marco

Ciao Marco,
grazie per le informazzioni.

Saluti,
Pedro

Pedro Alves Wrote:
-------------------------------------------------------
> Hi,
> and (Ti+Zr) ?
> A Ti rich zircophyllite...

Rather it is Zr-bearing astrophyllite.

Hi Pavel,
your hypothesis seems to be more correct.
Since, in this particular case, we cannot see the F and the Fe content seems to be higher than the Mn one (not sure about that, and not sure also it this may be important).

Cheers,
Pedro

Real Zircophyllite should be Mn-dominant - it is Zr analogue of kupletskite, not astrophyllite.
what about F content, I am think all is OK with it in this mineral. F contents in such rocks are usually enough high.

Two problems then.
First the Mn content, wich is probably more conclusive. The Zr is not the 'big problem'.
Right?

Dear All,

I really appreciate this stimulating discussion, however, I feel the need to remind to you (as it
has been explained to me) that from qualitative EDS analysis it is not, and I repeat, it is not
possible to estimate accurately the relative abundances of the elements. Consequently,
every assignment must be considerd a mere and often a meaningless, speculation.

On the contrary, the attribution was based also on preliminary x-ray diffraction data, that are
probably a better method of identification than the "eye" of an experienced amateur or even a
professor in mineralogy.

Finally, I may be wrong, but there are many groups of minerals (e.g. H, B, Be,
REE and Li bearing minerals), in which also routinary structural and quantitative chemical
analyses, can not be far from sufficient to properly define a species.