Cadmoindite, formula- (CdIn2S4) is a rare cadmium indium sulfide mineral discovered in Siberia around the vent of a high-temperature (450–600°C) fumarole at the Kudriavy volcano, Iturup Island in the Kuril Islands. It has also been reported from the Kateřina Coal Mine in Bohemia, Czech Republic.

It is an isometric-hexoctahedral mineral containing cadmium, germanium, indium, iron, sulfur, and zinc.

General Information

  • Category: Sulfide mineral (Thiospinel group)
  • Formula: CdIn2S4
  • Crystal system: Cubic
  • Crystal class: Hexoctahedral (m3m).


  • Formula mass: 470.32 g/mol
  • Color: Black to dark brown
  • Crystal habit: Microscopic octahedral crystals
  • Fracture: Conchoidal
  • Luster: Adamantine
  • Diaphaneity: Translucent
  • Optical properties: Isotropic

Occurrence: As the bottom layer in fumarolic sublimate crusts.

Association: Pyrite, cadmian wurtzite, rhenium disulfide, greenockite, lead-bismuth sulfide.

Crystal Structure

CdIn2S4 exhibits the spinel structure, which can be described by a cubic unit cell with 8 tetrahedrally coordinated and 16 tetrahedrally coordinated cation sites. The distribution of Cd(II) and In(III) over the cation sites is difficult to elucidate from standard X-Ray Diffraction techniques because the two species are isoelectronic, but both Raman spectroscopy measurements on synthetic samples and density functional theory simulations indicate that about 20% of the tetrahedral sites are occupied by In(III) cations.


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