Ichnusaite (pronounced iknusa-ait) is a very rarely found mineral.

[3] 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.

[5] This locality is also a place of discovery of the second natural thorium molybdate - nuragheite.

[2] The main features of the crystal structure of ichnusaite are:[2] This article about a specific mineral or mineraloid is a stub.