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Phosphate

Meta-autunite

Ca(UO₂)₂(PO₄)₂·6H₂O
Hardness2–2.5
Crystal systemTetragonal
ClassPhosphate
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Meta-autunite specimen

Meta-autunite Locality: São Pedro claim, Malacacheta , Mucuri valley, Minas Gerais , Southeast Region, Brazil ( Locality at mindat.org ) Size: 4.5 x 3.0 1.7 cm. A STRIKING and AESTHETIC specimen of rosettes and books of lustrous, lemon-yellow autunite blades from well-known Sao Pedro Claim, Malacacheta, Brazil. An outstanding example of this species from this locality. Ex. Elling collection. SPECTACULAR lemon-yellow fluorescence. — Photo: Robert M. Lavinsky · CC BY-SA 3.0

Meta-autunite

Meta-autunite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Ca(UO₂)₂(PO₄)₂·6H₂O.

It crystallizes in the tetragonal crystal system (space group P4/nmm). It is a member of the Meta-autunite structural group.

Key properties: Mohs hardness 2–2.5; specific gravity 3.35–3.55; Pearly to dull luster; optically uniaxial.

IMA symbol Maut, grandfathered status — known before the IMA’s founding, named in 1904.

A secondary mineral, formed as dehydration pseudomorphs after autunite.

It is found associated with Autunite.

The prefix meta- denotes the dehydration product of autunite.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more M minerals or help write this entry.