Basalt
Basalt pebbles near the southern tip of La Palma slowly transforming into black sand typical to volcanic oceanic islands. Basalt sample collected near the Giant's Causeway, Northern Ireland. Width of sample 8 cm. Gabbro is a coarsegrained (intrusive) equivalent of basalt. This sample of gabbro comes from La Plama. La Palma is an oceanic island, but some parts of it are uplifted and there ...