2.9" Marcasite Crystals on Bladed Barite - Morocco
This specimen contains marcasite and bladed barite. The barite has a slight yellow coloration with a bladed formation and is peppered in small marcasite crystals.
Barite, commonly spelled baryte, is well-known for its great range of colors and varied crystal forms and habits. It is a heavy mineral consisting of barium sulfate, and typically has the chemical formula of BaSO4. The barite group consists of baryte, celestine, anglesite and anhydrite. It's generally white to colorless and is the main source of barium.
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.