What is "tancaite-"

Tancaite-(Ce) is a very rare molybdate mineral with the formula FeCe(MoO)•3HO. It was found in Punta de Su Seinargiu locality on Sardinia, Italy. Red crystals of tancaite-(Ce) resemble modified cubes, but the mineral is trigonal (space group R-3). The type locality of tancaite-(Ce) is also a place of discovery of other molybdate minerals, including thorium molybdates ichnusaite and nuragheite.