The Uniqueness of El Lastre

 It is the only black-sand beach at Region of Murcia.

Unlike the volcanic beaches typical of the Canary Islands or the Caribbean, the distinctive dark color of Playa del Lastre / Lastre Beach / Ballast Beach (in Portmán, La Unión) stems from a mining and industrial origin unique to Region of Murcia.

Why is it black? For decades, particularly between the 1950s and 1990s, intense open-air ore-washing activity in the Mining Mountain Range of La Unión generated millions of tons of tailings and metal-rich sediments. The grayish, jet-black hue of the sand is due to the high concentration of iron-bearing minerals, sulfides, and residues of pyrite, magnetite, and galena that were deposited in the bay; marine action eventually ground these materials down and settled them along the shoreline.

Here, a panoramic view.