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Two New Feet

We are having quite a golden time for new mineral species additions to e-Rocks.

This short blog features news from from Jason Smith and Volker Betz regarding two new phosphate minerals from Foote Mine in North Carolina, USA. Apologies for the pun in the title.

The new minerals aniyunwiyaite and fanfaniite were discovered in a boulder in the dumps: when samples were analysed one proved to be triclinic, but with similar chemistry to kingsmountite.

Aniyunwiyaite is now the triclinic ‘analogue’ of kingsmountite, with ordered Fe and Mn on the Ca site.

During this study another new species, fanfaniite, was described, which is the Mn (or Fe depleted) analogue of monoclinic kingsmountite.

If this is confusing the table below tries to illustrate the relationship. It is said that it is likely that many specimens of ‘kingsmountite’ are indeed aniyunwiyaite. 

Aniyunwiyaite - Foote Mine, NC, USA. (4.8mm FOV) - Jason Smith


Relationship between Kingsmountite, Fanfaniite & Aniyunwiyaite.
Species Group Formula System
Kingsmountite Montgomeryite Ca4(Fe2+,Mn2+)Al4(PO4)6(OH)4 · 12H2O Monoclinic
Fanfaniite Montgomeryite Ca4MnAl4(PO4)6(OH)4·12H2O Monoclinic
Aniyunwiyaite   Ca3Mn2+Fe2+Al4(PO4)6(OH)4·12H2O Triclinic


General formula for Montgomeryite group  is Ca4BC4(PO4)6(OH)2-4.12-14H2O
Where B is (Fe, or Mg, or Mn)2+ and C is  (Al or Fe)3+

As you can see aniyunwiyaite fits the formula as it is B = Mn2+Fe2+ and C = Al3+ but is triclinic so is related, but not classed in the same group.

We do not currently have any listings for aniyunwiyaite, but Volker Betz has kindly listed a specimen of fanafaniite, see link below.

Being in the Montgomeryite group fanfaniite is also related (analogue) to zodacite by exchange of Al3+ to Fe3+ in the C position in the general formula above.

Fanfaniite - Foote Mine, NC, USA. (c 5mm FOV) - Volker Betz


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