Dollar - Disc shaped Pyrite or Marcasite with a radial form. Most "Dollars" are Pyrite; only few are Marcasite. When the term Dollar is used alone, it refers to a Pyrite Dollar. In some localities, dollars are composed of both Pyrite and Marcasite (Pyrite on the inner layer, Marcasite on the outer layer. Such dollars are called "Pyrite Marcasite Dollars".