Freestanding Pyrite - Peru
A distinctive piece of pyrite with a textured, golden front and smooth, dark shale back. The mineral formed naturally as a metallic coating on the host rock.
The brassy yellow surface has a slightly rough texture and bright metallic lustre. Although it can't be fully appreciated from our photos, it reflects light beautifully.
The back is smooth with a dull lustre, meaning it reflects minimal light.
Pyrite can sometimes form coatings like this on shale.
It commonly forms in low-oxygen marine sediments, where iron reacts with sulphur produced by bacteria during the decay of organic matter. That's why it's often associated with black shales.
Black shale is a fine-grained sedimentary rock formed from compacted mud that contains abundant organic material, giving it its dark colour.
Pieces of pyrite like this are less commonly sold, as this iron sulphide mineral, known for its brassy-yellow colour, is more often seen as cubes or crystal clusters.
Prehnite
