Pyrite from Ambas Aguas, La Rioja, Spain

Pyrite from Ambas Aguas, La Rioja,

Narrave, Spain

Best quality 

In Ambas Aguas there are numerous outcrops that have been known for over 100 years, which are worked for pyrite, but only for collecting and decorating purposes. They are located along the streams around the area, and occur as they cross Cretaceous sedimentary layers that are affected by mineralizing hydrothermal fluids

An essential book about minerals :

MINÉRAUX – LE GUIDE DES PASSIONNÉS – JULIEN LEBOCEY