New Mexico Mineral Symposium — Abstracts

Over the course of 25 years, the pyrites of Navajun, Spain have been for the author, a source of geological and mineralogical interest. In 1993, the author was sent to Spain by his oil company employer to investigate the Spanish offshore oil fields in the Mediterranean, south of Barcelona. Overlying these offshore Jurassic carbonate oil reservoirs are Cretaceous limey shales and carbonate rich marls which cap and seal the oil reservoirs. These “seal rocks” contain microscopic pyrites. These same Cretaceous limey shales and carbonate rich marls found onshore Spain in the Cameros Basin, host the pyrites of worldwide fame. In 2018, the author and his wife vacationed in Spain and took several days on a journey to visit and self-collect at the famous, “Mina Ampliacion de Victoria,” 4 km N/NW of the village of Navajun, Cervera District, La Rioja Province, Spain.

The presentation will describe the geological and mineralogical occurrence of these incredible and unique pyrite specimens in a trip back to Spain. The interplay of a unique stratigraphic record leading to the pyrite formation will be discussed. Pyrite is found in over 43,836 worldwide locations, per Mindat (2021). But Navajun is an iconic location known for its almost perfect cubic crystals in a striking occurrence. Some of these cubic crystals are up to 19 centimeters (7.5 inches) on a side. These perfect crystals, to non-collectors, are believed to be manmade and on discovery of the truth, show expressions of amazement or disbelief.

For those who keep a bucket list of collecting locations to visit, Navajun should be found in their top 10. The author and his wife want to thank Victoria Mine owner, Pedro Ansorena Conde and his able associate, Raul Sesma for indulging us on the mine trip and making it a grand part of our visit to Spain. Incredible food and wine and world class transportation also added to the enjoyment of a return visit to Spain