Spanish Pyrite from Ambas Aguas

Ambas Aguas, in Muro de Aguas, La Rioja, is a nearly abandoned hamlet whose small surrounding quarries produce what are considered some of the world’s finest pyrite specimens. Say La Rioja pyrite and most people think of Navajún’s almost perfect cubes, but Ambas Aguas goes in a completely different direction.

Its pyrite is known for pyritohedra and twins, built on the cube with many complex modifications, with fine striations and stepped terraces on the faces and a bright metallic luster in brassy silver-gray. The specimens come in two forms: loose, free-standing crystals that can be admired from every angle, and crystals preserved on white host rock, where the pale stone sets off the metallic luster in a clean, sharp contrast. Rarer habits such as the iron cross and the pinecone sometimes appear.