Iron Pyrite: "Fool's Gold"

Iron Pyrite: "Fool's Gold"

Pyrite Cube in Marl

Pyrite is an iron sulfide generated by sulphur reacting with iron present in sedimentary rock (limestone and sandstone) in a reducing environment. It comes in an astonishing array of forms -- from discoids (also known as sunflowers), to suns, to perfect cubes -- all in the same glittering, glassy, golden shade.

When found with quartz crystals (as it often is), the encrustation of pyrite causes the quartz to form delicate, needle-like points unlike any you've seen before! Pyrite is also part of what makes Lapis Lazuli (a vivid blue rock with pyrite veins) such a popular stone for tumbling, beads and carving.

Iron Pyrite has so often been mistaken for gold that its better-known name is "fool's gold." It has a warm yellow color, it's metallic, and it glitters and sparkles just like the real thing. So how can you tell if you've found gold, or simply fool's gold?

  1. Try using a straight pin to stab the specimen. Gold is a very soft metal and will bend or break when you do this; iron pyrite is much harder and won't budge.
  2. If you have a 10x magnifier (or loupe), examine your find closely. Pyrite has a cubic structure; gold does not
  3. You can also use a drop of nitric acid to test your specimen. (Caution is advised.) Nitric acid will turn iron pyrite black, but gold will remain the same color.

To complicate things even further, pyrite and gold are often found in the same locations. If you're out gold-panning and think you've found gold, look closely. If it's floating all over the pan, it's just pyrite. But if it settles to the bottom, you've gotten lucky!


  1. Charles Charles

    Pyrite is normally not magnetic. You should do a little research before spreading false information.

  2. Tom Tom

    Classic "Fool's Gold" or iron pyrite in not magnetic despite the iron content. Pyrrhotite an unstable form of pyrite which quickly weathers to dark rust brown (not shiny like pyrite) is magnetic, but rarely would you see a fresh unoxidized piece on the surface, so this 'test' is not valid.

Leave a comment
* Your email address will not be published