Offretite from Mont Semiol, France

Offretite from Mont Semiol, Châtelneuf, Montbrison, Loire, Auvergne-Rhône-Alpes, France

Micro specimen of Offretite from its type locality, Mont Semiol, France.

The blue-grey mineral is possibly Montmorillonite, but it hasn't been analysed.

Comes boxed with our ID label and a former owners label - hopefully, this one will be popular amongst collectors of French minerals.