Images
Formula: (Ni,Cu)Al4(NO3,SO4)2(OH)12.14H2O
Hydrated nitrate, nickel- and copper-
bearing mineral
Crystal system: Monoclinic
Specific gravity:
Colour: Sky-blue
Environments
Sedimentary environments
Cave deposits
On exposure to the atmosphere, freshly collected blue nodules of hydrombobomkulite lose water and are
transformed into
mbobomkulite in a few hours. The dehydration is irreversible
(AM 67: 415-416).
Localities
At the type locality, the Mbobo Mkulu Cave, Mbombela, Mbombela Local Municipality, Ehlanzeni District Municipality,
Mpumalanga, South Africa, hydrombobomkulite is formed by the interaction of solutions of nickel sulphate from
weathering Cu–Ni-bearing sulphides with aluminosilicate minerals and nitrate derived from bat guano. Associated
minerals include allophane,
mbobomkulite and
chalcoalumite
(HOM).
Hydrombobomkulite from Mbobo Mkulu Cave -
Image
At the Jomac Mine, White Canyon Mining District, San Juan County, Utah, USA, hydrombobomkulite occurs in a
sedimentary U–V deposit. Associated minerals include
oswaldpeetersite, cuprite,
antlerite, goethite,
lepidocrocite,
mbobomkulite,
sklodowskite and gypsum
(HOM).
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