Fools Gold -

: It commonly forms perfect cubic, octahedral, or pyritohedral (12-faced) crystals.

: When scraped against unglazed porcelain, pyrite leaves a greenish-black streak , while real gold leaves a golden-yellow streak . Fools Gold

Pyrite forms in a wide variety of environments, including igneous, metamorphic, and sedimentary rocks. The Many Faces of Fool's Gold | American Scientist : It commonly forms perfect cubic, octahedral, or

: Derived from the Greek word pyr ("fire"), pyrite produces sparks when struck against steel, a property used by ancient civilizations for fire-starting. Geological Formation and Occurrences : It commonly forms perfect cubic