To my delight the Société Géologique de France sent me their geologically themed face coverings (€5 each or €15 for all four, and around €3 postage to the UK). Designed for non-medical use they can be worn for four hours and are machine washable at 60° C. Designs include a pair of cream on black illustrations of the ammonite laevigatus (James Sowerby) from southern England.
David Nowell