Think rocks take millions of years to form? Wrong: it could be just decades

Astounding study of rocks formed from foundry waste on Cumbrian coast could throw geological precepts into doubt

Rocks take thousands to millions of years to be made, right? Wrong. Researchers have discovered that industrial waste has forged itself into rock over the course of just a few decades. This astounding discovery, made at Derwent Howe on the UK's Cumbrian coast, challenges theories about how rocks are formed.

The rocks, which are a glassy texture and blue-grey colour, are made from slag, leftover from the iron and steel-making foundries that operated near Derwent Howe in the 19th and 20th centuries. Samples show the rocks contain many of the chemicals found in ordinary sedimentary rocks, but in this case hardened into solid rock within 35 years. An aluminium drinks tab dating to 1989 or later and a 1934 George V coin, fused into the new rock, are proof of its rapid formation.