Greenish crystal aggregates of rossite and metarossite, two rare vanadates from Colorado (USA). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Metarossite
Metarossite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula CaV⁵⁺₂O₆·2H₂O.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: specific gravity 2.8; Dull to pearly luster; optically biaxial.
IMA symbol Mrs, grandfathered status — known before the IMA’s founding, named in 1927.
Found in veinlets in carnotite-bearing sandstone (Bull Pen Canyon, Colorado, USA).
It is found associated with Rossite, carnotite, gypsum (Bull Pen Canyon, Colorado, USA).
The name refers to its relation to rossite, from which it may form by dehydration.