Fool's gold is a mineral which looks like gold, but has distinct properties which can help distinguish it from real gold easily. The term ‘fool's gold' comes from the times of the Gold Rush, when miners and prospectors thought they'd found gold while prospecting but what they'd actually found was iron pyrites or fool's gold as it came to be known later. In spite of the superficial similarities in appearance, it is quite easy to identify one from the other with the help of a few tests. To find out what methods can be used to tell the real thing from the imposter, read through the steps described below.
Color. Pyrites or fool's gold has a lighter-yellow color with a distinctive brassy sheen. Real gold, on the other hand, has a more silvery appearance, giving the gold a dull sheen.
Odor. Iron pyrites has a strong component of sulfur which gives it the typical smell of rotten eggs. Gold does not have sulfur and therefore becomes easy to identify.
Magnetic attraction. Use a magnet to test out the difference between real gold and pyrites. Pure gold does not contain iron, while pyrites does. Hence, a magnet will have no impact on real gold while a piece of pyrites will be attracted to a magnet since it contains iron.
Hardness. Gold has a low count of hardness when compared with fool's gold. To check whether the piece you have is real or not, use any metal object, made of copper or steel. Use the mineral piece to scratch the copper object. Gold, being softer than copper, will not be able to leave a scratch, whereas fool's gold will leave a scratch on the object since pyrites is a harder metal than copper. If you use steel to test out the difference, a harder mineral like pyrites will strike a spark, but pure gold being softer, is also malleable and will soften and bend when struck against steel.
Powder content. When a mineral is rubbed against hard white porcelain, it leaves a powdery colored residue which can be used to identify the mineral. In the case of real gold, it will leave a pure yellowish residue, while fool's gold will leave a greenish-black residue on account of the iron and sulfur content.
Shape. Nuggets of fool's gold are usually found in cubic or octahedron shapes, gold tends to be found as sheets or rectangular bars.
With the above six tests, the job of distinguishing pure gold from fool's gold becomes very easy. What's more, you don't need to undertake complex testing to tell the difference.