This pyrite is from Navajun, La Rioja, Spain.The deposits in this area are cretaceous and are 65 to 145 million years old. This locale is famous for the outstanding crystals found there. They have sharp cubic habits, a bright golden color and mirror luster. Pyrite is a sulfide mineral containing the elements Fe and S. It can have a variety of crystal habits including cubic. It is sometimes referred to as “fools Gold” for obvious reasons. This piece consists of a marlestone matrix that contains two exposed pyrite crystals and a spherical cluster of chamosite crystals. Chamosite is in the Chlorite Group and contains the elements Al, Fe, H, Mg, O and Si. The primary pyrite measures 30 mm across (diagonally). The chamosite crystal cluster is approximately 10 mm across and is blue in color. This specimen measures 2 1/2 x 2 x 1 3/4 inches or 63 x 50 x 45 mm as displayed in photo one.