These pyrite crystals are from the Huanzala Mine in the Huallanca District of the Dos de Mayo Province, Huanco Department, Peru. This a predominately lead-zinc mine but 63 other mineral species can be found there. It is one of the premier locales for pyrite specimens. Pyrite is an iron sulfide that contains the elements Fe and S and can be found in a variety of crystal habits. This piece consists of a mound-like formation with terminated prism faces on the sides and top. The rear is a former crystal attachment point and the bottom has a healed surface.. The pyrite crystals have sharp well defined habits with complex secondary growth on the crystal faces. They have a bright gold color and metallic luster. The largest crystal is approximately 41 mm across. This piece measures 3 1/16 x 2 1/16 x 1 1/2 inches or 77 x 52 x 38 mm.