Nashite

nashite

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Formula: Na3Ca2[(V4+V5+9)O28].24H2O
Hydrated vanadate
Crystal system: Monoclinic
Specific gravity: 2.350 calculated for the empirical formula, 2.343 calculated for the ideal formula
Hardness: 2
Streak: Light bluish green
Colour: Bluish green
Luminescence: Does not fluoresce under short wave or long wave UV
Environments

Sedimentary environments
Hydrothermal environments

Nashite is a relatively new mineral, approved in 2012 but to date (October 2025) reported only from the type localities.

Localities

There are two co-type localities, the Saint Jude Mine, Slick Rock Mining District, Colorado, USA, and the Little Eva Mine, Yellow Cat Mesa, Thompsons Mining District, Grand County, Utah, USA.

At the Saint Jude Mine, Slick Rock Mining District, Colorado, USA, nashite occurs in a similar assemblage to that at the Little Eva mine, see below.

In the Little Eva mine, Yellow Cat Mesa, Thompsons Mining District, Grand County, Utah, USA, nashite crystals were found growing as blades on a corvusite-montroseite - bearing sandstone block, intimately associated with calciodelrioite, calcite, gypsum, huemulite, pascoite, rossite and sherwoodite. Other minerals found nearby include andersonite, ansermetite, cobaltomenite, dickthomssenite, ferroselite, lasalite, martyite, melanovanadite, natrozippeite, schrockingerite, native selenium, tyuyamunite and uraninite.
Nashite from the Little Eva Mine - Image.

At both type localities nashite is rare. It forms from the oxidation of montroseite-corvusite assemblages in a moist environment. Mining operations have exposed unoxidised and oxidised phases; in addition to nashite, other mixed-valence V4+/V5+ vanadium minerals such as sherwoodite and melanovanadite are found in the association, which suggests that local oxidising conditions can be controlled by the presence of organic matter and phases such as pyrite. Under ambient temperatures and generally oxidising near-surface environments, water reacts with pyrite in the deposit to form aqueous solutions with relatively low pH (high acidity), forming various secondary vanadate phases.
Crystals of nashite are equant to tabular and commonly occur in stacked parallel intergrowths. Individual crystals are up to 0.3 mm in maximum dimension. Nashite is transparent and bluish-green, with a light bluish green streak. and a subadamantine lustre. (CM 51.1.27-38).

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