Daubréelite

Crystal System: Cubic
Status of Occurrence: Confirmed Occurrence
Distribution: Rare
Chemical Composition: Iron chromium sulphide
Chemical Formula: FeCr2S4
Method(s) of Verification: Pontllyfni - EMPA (Graham et al., 1977).

Chemical Group:

  • Sulphides

Geological Context:

  • Igneous/metamorphic extraterrestrial
Introduction: this is a thiospinel group mineral (with a formula of M3S4 in which S is sulphur or occasionally selenium and M is one or more of the following metals: Fe, Co, Ni, Cu, Cr, In). Daubréelite is found typically in extraterrestrial material. The type locality is a meteorite impact site in Mexico.
Occurrence in Wales: the Welsh occurrence of daubréelite is related to one of very few meteorite falls actually recovered from Wales. The meteorite fell on April 14th, 1931 at 11:53am on Coch-y-Bug Farm, Pontllyfni, Gwynedd and a fragment of 5 oz was recovered (King, 1932). For more data on this event, please visit the 'About Mineralogy' pages.

Key Localities:

  • Coch-y-Bug Farm, Pontllyfni, Gwynedd: daubréelite is present in the forsterite chondrite meteorite from this locality, along with troilite, as inclusions varying from <1 µm to 25 µm across, associated with metal alloys (taenite and kamacite). The sulphides and metals make up 46 wt% of the meteorite, and are intergrown with olivine and orthopyroxene (Graham et al., 1977).

References:

  1. Graham, A.L., Easton, A.J. & Hutchison, R., 1977. Forsterite chondrites; the meterorites Kakangari, Mount Morris (Wisconsin), Pontlyfni, and Winona. Mineralogical Magazine, 41, 201-210.
  2. King, A., 1932. The meteorite of 1931 April 14. Journal of the British Astronomical Association, vol 42, 328-332.