The geology of Glomel is renowned for its exceptionally rich
andalusite deposit, known for having the highest andalusite content in the world. This unique mineral, prized for its high-temperature resistance, has been extracted at the
Guerphalès mine since 1970. The site, operated by
Imerys, plays a crucial role in the global andalusite market, producing 65,000 tonnes annually, which accounts for 20-25% of global output. ==Map==