Falsterite
# Falsterite

Falsterite is a rare phosphate mineral with the formula $Ca_2MgMn^{2+}_2(Fe^{2+}_{0.5}Fe^{3+}_{0.5})_4Zn_4(PO_4)_8(OH)_4(H_2O)_{14}.$ It is a pegmatitic mineral, related to the currently approved mineral ferraioloite.

## Occurrence and association

Falsterite was found in Palermo No. 1 pegmatite, North Groton, Grafton County, New Hampshire, US. Co-type locality is pegmatite at Estes quarry, Baldwin, Cumberland County, Maine, US. Falsterite is a product of alteration of triphylite and sphalerite.

## Crystal structure

Main features of the crystal structure of falsterite, which is somewhat similar to that of schoonerite, are:

* chains of $Fe^{n+}O_6$ octahedra, displaying edge-sharing
* chains of $ZnO_4$ tetrahedra, that display corner-sharing
* sheets, parallel to {010}, formed by linking the above two types of chains by $PO_4$ tetrahedra
* slabs formed by linking the sheets with $MnO_6$ octahedra and $CaO_7$ polyhedra

The slabs are bridged by dimers of $MgO_6$ octahedra that display edge-sharing. Magnesium-bearing octahedra share edges with zinc-bearing tetrahedra.

