Pyrite is the most common and abundant of all sulfide minerals. Chemically iron sulfide, it is brittle and known commonly as 'fools' gold' because tiny particles have a metallic golden hue and are easily mistaken for flecks of native gold. Pyrite is chemically identical to marcasite, but pyrite has isometric (cubic) symmetry and marcasite is orthorhombic. Pyrite crystals are typically cube shaped or octahedral, as in this specimen from Quiruvilca, Peru, but also display a huge variety of other forms. Its abundance and spectacular crystals make pyrite one of the most popular of all collector minerals.