Do you think rocks are just … well, rocks? These natural mineral combinations have done more than just sit around—they've built the Earth's crust and helped humans shape history. From Stone Age tools to the minerals powering modern civilisation, rocks have been essential throughout our journey. International Rock Day celebrates this enduring impact, inviting us to explore the science of rocks, admire their natural beauty and recognise the rich variety they add to our world. If you're wondering where to see geology in action, Iceland is a great place to explore. Today's image takes us to Kálfshamarsvík—a secluded cove on the country's remote Skagi peninsula. Unlike Iceland's famous black sand beaches, this cove's shore is strewn with large, smooth pebbles, while its fiery volcanic past still reveals itself in the towering cliffs. Here, evidence of volcanic activity is on full display in the form of rare hexagonal basalt columns.

Thousands of kilometres away, Narcondam—India's easternmost island—offers another striking example. This tiny volcanic landmass, rising 710 metres above sea level in the northern Andaman Sea, is made up primarily of andesite, a fine-grained volcanic rock typically formed in volcanic arcs.