What is Cadmoindite?
Cadmoindite is a rare cadmium indium sulfide of the thiospinel group, known from altered coal-waste and sulphide environments.
Mineralogy and structure
The reference formula is CdIn2S4. Cadmoindite belongs to the sulfides and crystallises in the cubic system. The cubic spinel-type structure places cadmoindite in the linnaeite subgroup. Its rarity and possible association with toxic elements make analytical identification and careful storage essential.
Colour and appearance
Typical colours include black, dark grey and brownish black. For small or complex mineral species, crystal size, transparency, lustre and matrix association are often more diagnostic than colour alone.
Formation and localities
Cadmoindite forms in or is associated with high-temperature sulphide assemblages and burning coal-waste dumps. Important documented localities include the Czech Republic and other cadmium-indium sulphide occurrences. A precise mine or geological setting is preferable to a broad country label when it is known.
Collecting and care
Cadmoindite is best treated as a labelled reference or collector specimen. Protect fragile crystals from impact and humidity changes. Arsenic-, cadmium-, lead-, thorium- and selenium-bearing minerals should not be cut, ground or used in jewellery; wash hands after handling and keep them away from food and children.
