Iron Pyrite is commonly called 'fool's gold' because it has a warm yellow color and glitters and sparkles like gold. Formed over 100 million years ago by sulfur reacting with iron, these cubic specimens of FeS2
are still being found in the sedimentary limestone and sandstone of the Navajan region of Spain.
Common tests to distinguish iron pyrite from gold:
Gold does not form a cubic crystal
Gold is very soft and will bend or break when stabbed with a straight pin; the much harder pyrite will not.
Gold is not attracted to a magnet; pyrite is.
Gold is much heavier than pyrite.
Gold will flatten when hit with a hammer, while pyrite will shatter. Pyrite Cube
One cube, ca. 2.5 cm (1 in.) per side, 90 g. Pyrite in Matrix
One or more cubes in sandstone, ca. 1 cm cube in a 2 x 3 cm matrix, 35 g.