Ichnusaite

Ichnusaite (pronounced iknusa-ait) is a very rarely found mineral. Ichnusaite is a natural compound of thorium and molybdenum with the formula Th(MoO4)2·3H2O. It was discovered in Su Seinargiu, Sarroch, Cagliari, Sardegna, Italy in 2013. The name is from the old Greek name of Sardinia, Ιχνουσσα, Ichnusa. This locality is also a place of discovery of the second natural thorium molybdate - nuragheite.

Occurrence and association
Muscovite, nuragheite, and xenotime-(Y) are the associates of ichnusaite.

Notes on chemistry
Ichnusaite is chemically pure.

Crystal structure
The main features of the crystal structure of ichnusaite are:
 * electroneutral Th(MoO4)2(H2O)2 (100) sheets
 * ThO7(H2O)2 and MoO4 polyhedra polymerize to give the above sheets
 * sheets are stacked along [100] and held by hydrogen bonds