Cadmoindite mineral

Cadmoindite is the cadmium-indium sulfide mineral species CdIn2S4, approved as IMA 2003-042 in the September 2026 IMA-CNMNC list. Chaplygin and colleagues (2004) described natural octahedral crystals from fumarolic crusts at Kudriavy volcano on Iturup Island in the Kuril Islands. Microscopy, fifteen electron-microprobe analyses and powder X-ray diffraction support a cubic thiospinel assignment, compared separately with synthetic CdIn2S4 and the iron analogue indite. The analyzed natural grains contain Fe and Zn and smaller Ge and Se contributions; ideal end-member stoichiometry is not a claim of specimen purity. Crystals occur in both pyrite-associated and pyrite-free assemblages, with cadmium-bearing wurtzite and other phases. The paper reports sampling roughly 15-30 centimetres below the crust surface at outgoing-gas temperatures of 450-600 degrees Celsius. Those are field sampling conditions, not directly observed crystallization temperatures or biological incubation conditions. Formation from cooling gas, including the proposed breakdown of metal chlorides, is inferred from the occurrence and cited gas modelling; it was not demonstrated by a controlled transformation experiment on this mineral. Separate laboratory synthesis conditions and electronic uses of synthetic CdIn2S4 do not establish recovery or deployment of natural cadmoindite. This species is distinct from elemental cadmium or indium, indite, bulk fumarolic crust and manufactured CdIn2S4 considered only by formula. The specimen study does not establish a bulk resource grade or extraction yield. No microbial mechanism or constituent-derived criticality designation is assigned.

Record source: data/records/cadmoindite.yaml