What is Vanoxite?
Vanoxite is a rare hydrated mixed-valence vanadium oxide, usually dark and fine-grained in secondary vanadium deposits.
Mineralogy and structure
Reference formula: V6O13·8H2O. Vanoxite has historically been reported with variable or uncertain hydration and mixed V4+/V5+ chemistry. No suitable public COD model was selected in this batch; the guide intentionally avoids a false precision lattice. Vanoxite is classified with vanadates and has trigonal crystal symmetry. Typical hardness is 2–3 on the Mohs scale and specific gravity is approximately 2.8–3.2.
Colour, lustre and habit
Typical colours include black, blue-black, brown-black, dark green. The usual massive, crusty, granular habit and sub-metallic, dull, earthy lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Vanoxite forms in or is associated with oxidised vanadium ores, sandstone-hosted deposits, mine workings and secondary cavities. Important documented localities include the western United States, Argentina, Mexico and other vanadium districts.
Dark mixed-valence chemistry in an oxidised ore
Vanoxite is a reminder that some attractive labels represent difficult mineral chemistry. A documented deposit and analytical record are more valuable than assigning a rigid formula to every dark crust.
Collecting and care
Keep enclosed and dry, avoid dust and acids, and do not grind or heat unknown vanadium-bearing material.
