Ochre formation

The ochre sands result from a deep chemical modification of green marine sands. About 100 million years ago, green sands emerged and were altered under a hot and humid climate which transformed into, amongst others, ochre sands. It is from these sands extracted in quarries that ochre is made. Warning, mountain biking in the heart of the Provençal Colorado in Rustrel is forbidden, as is the sampling of ochre sands in natural environment.