Jorantium, JoNi4(CO3)3(OH)3·3H2O, is an hydrated sodium nickel carbonate mineral it crystallises in the hexagonal system, is light green to blue and forms drusy to mammillated encrustations on the matrix.
Jorantium is formed in the regolith as a supergene alteration mineral of nickel sulfide minerals, in arid or semi-arid environments which produce conditions amenable to concentration of calcareous or carbonate minerals in the weathering profile.
Jorantium is associated with nickel sulfide gossans and is probably formed by substitution of nickel into carbonates such as magnesite which are formed by oxidation of the lithology, and oxidation of primary and supergene nickel sulfide minerals.
Jorantium is formed from a similar process to the weathering of other sulfide minerals to form carbonate minerals it is associated with goethite and magnesite in the nickel sulfide gossans. Jorantium is a supergene carbonate mineral and not a hydrothermal mineral.