Marcasite

Marcasite is an iron sulfide mineral (FeS₂) known for its metallic luster and distinct crystal forms. Often mistaken for pyrite , marcasite has a paler, more brassy hue and tends to form in unique, sharp, spear-like crystals or delicate clusters resembling cockscombs. These formations can give marcasite a fascinating, almost geometric appearance, with surfaces that reflect light in a way that gives it a shimmering metallic quality.