Nuragheite

Nuragheite is a rare^[3] natural thorium molybdate, formula Th(MoO₄)₂·H₂O, discovered in Su Seinargiu, Sarroch, Cagliari, Sardegna, Italy.^[2] This locality is also a place of discovery of the other thorium molybdate - ichnusaite, which is a trihydrate.^[4]

Nuragheite
General
Category	Molybdate minerals
Formula	Th(MoO4)2·H2O
IMA symbol	Nur[1]
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	P21/c
Unit cell	a = 7.36, b = 10.54 c = 9.49 [Å], β=91.88° (approximated)
Identification
Color	Colorless
Crystal habit	Thin tablets
Cleavage	{100}, perfect
Tenacity	Brittle
Luster	Pearly adamantine
Streak	White
Specific gravity	5.15 (calc., approximated)
Other characteristics	Radioactive
References	[2][3]

Occurrence and association

Nuragheite is a part of molybdenum-bismuth mineralization. It coexists with ichnusaite, muscovite, and xenotime-(Y).^[2]

Notes on chemistry

Nuragheite is chemically pure.^[2]

Crystal structure

The crystal structure of nuragheite is composed of (100) layers with ^IXTh-centered polyhedra and Mo-centered tetrahedra.^[2] It is thus similar to that of ichnusaite.