Honessite

honessite

millerite

violarite

bravoite

Images

Formula: (Ni_1-xFe³⁺_x)(SO₄)_x/2(OH)₂.nH₂O (x < 0.5, n < 3x/2)
Hydrated sulphate containing hydroxyl, woodwardite group, nickel-bearing mineral
Specific gravity:
Hardness: 1 to 1½
Streak: Brownish white
Colour: Green, brown
Solubility: Insoluble in water. Soluble with slight effervescence in dilute acid solutions. Free oxygen is liberated (Mindat)
Environments

Hydrothermal environments

Honessite is derived from the oxidation of millerite and other primary nickel sulfides (Webmin). It may convert readily into hydrohonessite, depending on humidity and temperature (Mindat)

Localities

At Hagdale Quarry, Unst, Shetland Islands, Scotland, UK, honessite occurs on nickel-bearing chromite associated with reevesite, hydrohonessite and theophrastite (HOM, Dana).

At the type locality, Linden, Upper Mississippi Valley Mining District, Iowa county, Wisconsin, USA, honessite occurs as a green or brown powdery alteration of millerite, associated with millerite, violarite and bravoite (HOM).

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