The Lochaline quartz sand mine was opened in the summer of 1940 and in the following years it would become a crucial cog in the British war machine, producing sand that was shipped south to optical factories, where it was melted and worked into lenses for binoculars, periscopes and gunsights. Long before anyone came up with the concept of critical minerals, Lochaline was a site of military and national importance—even if few people, then as now, knew of its existence.
