This Specimen has been sold.
1.65" Colorful, Glittering Marcasite - Linwood Mine, Iowa
This is a colorful, 1.65" wide specimen of marcasite from the Linwood Mine in Buffalo, Iowa.
Marcasite is an iron sulfide mineral with the chemical formula FeS2. It is similar to pyrite in both its chemical composition and appearance, however it forms with a different crystal structure and is much more reactive to humidity. It is often found within sedimentary rock and hydrothermal deposits, and at one point was used for its sulfur content.