Outstanding yellow crystals of the rare Mo mineral mendozavilite-NaFe from the TL in Mexico (Cumobabi, La Verde District, Moctezuma Municipality, Sonora, Mexico). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Mendozavilite-NaFe
Mendozavilite-NaFe is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula [Na₂(H₂O)₁₅Fe³⁺(H₂O)₆][Mo₈P₂Fe³⁺₃O₃₅(OH)₂].
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Betpakdalite structural group.
Key properties: Mohs hardness 1.5; specific gravity 3.85; Bright yellow streak; Vitreous luster; optically biaxial.
IMA symbol Mdz-NaFe, IMA status: approved, named in 1982.
Found in the oxidized zone of some molybdenum-bearing hydrothermal mineral deposits.
It is found associated with Quartz, paramendozavilite (Cumobabi deposit, Mexico).
The mineral was named to honor Heriberto Mendoza Avila (b. 1924), Phelps Dodge exploration geologist, who found the first specimen.