Metatyuyamunite Locality: Mashamba West Mine, Kolwezi , Western area, Katanga Copper Crescent, Katanga (Shaba) , Democratic Republic of Congo (Zaïre) ( Locality at mindat.org ) Size: 4.5 x 1.7 x 2.3 cm. This specimen shows a vug filled with nicely terminated Metatyuyamunite crystals gathered together in sheaves up to 2 mm, associated with Malachite crystals. These are large for the species. These pieces where found in the mid 80’s together with the Carnotite specimens. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Metatyuyamunite
Metatyuyamunite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Ca(UO₂)₂(VO₄)₂·3H₂O.
It crystallizes in the orthorhombic crystal system (space group Pnam). It is a member of the Fritzscheite structural group.
Key properties: Mohs hardness 2; specific gravity 3.81–3.93; Adamantine, waxy if massive luster; optically biaxial.
IMA symbol Mtyu, grandfathered status — known before the IMA’s founding, named in 1954.
A common dehydration product of tyuyamunite in Colorado Plateau-type U–V deposits.
It is found associated with Tyuyamunite, carnotite, volborthite, vésigniéite, autunite, malachite, gypsum.
The prefix meta- denotes the dehydration product of tyuyamunite.