Falsterite

Falsterite is a rare phosphate mineral with the formula Ca2MgMn2+2(Fe2+0.5Fe3+0.5)4Zn4(PO4)8(OH)4(H2O)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: The slabs are bridged by dimers of MgO6 octahedra that display edge-sharing. Magnesium-bearing octahedra share edges with zinc-bearing tetrahedra.
 * chains of Fen+O6 octahedra, displaying edge-sharing
 * chains of ZnO4 tetrahedra, that display corner-sharing
 * sheets, parallel to {010}, formed by linking the above two types of chains by PO4 tetrahedra
 * slabs formed by linking the sheets with MnO6 octahedra and CaO7 polyhedra