Is Fools Gold Magnetic? Distinguishing Between Fools Gold and Real Gold

Frequently, people face confusion when trying to distinguish between fools gold and real gold, especially in ancient and modern legends. Understanding the true nature of these materials is crucial, as the magnetic properties of one can be quite deceiving. This article will explore the properties of both and provide methods to distinguish between the two.

Magnetic Properties

Fools gold, or iron pyrite (FeS2), is often mistaken for real gold due to its shiny, golden appearance. However, iron pyrite is not magnetic, although it does exhibit weak magnetic properties due to the presence of iron. In contrast, real gold (Au) is not magnetic at all.

Distinguishing Fools Gold from Real Gold

Color and Luster

Fools Gold (Iron Pyrite)

Has a brassy yellow color and a shiny metallic luster. Often appears more yellow than real gold.

Real Gold

Has a rich buttery yellow color and a softer luster.

Hardness

Fools Gold (Iron Pyrite)

Has a hardness of about 6-6.5 on the Mohs scale, meaning it can scratch glass.

Real Gold

Is much softer with a hardness of about 2.5-3.0 and can be scratched easily.

Streak Test

Fools Gold (Iron Pyrite)

When scratched on a piece of unglazed porcelain, it leaves a greenish-black streak.

Real Gold

Leaves a yellow streak when scratched on the same surface.

Density

Fools Gold (Iron Pyrite)

Has a density of about 5 g/cm3.

Real Gold

Has a much higher density around 19.3 g/cm3. This difference can be tested by weighing a sample in water.

Chemical Reactions

Fools Gold (Iron Pyrite)

Can react with acids. For example, it may produce hydrogen sulfide gas when treated with hydrochloric acid.

Real Gold

Does not react with most acids, although it can be dissolved in aqua regia (a mixture of hydrochloric and nitric acids).

Other Methods of Distinguishment

One of the easiest ways to distinguish between iron pyrite and real gold is to consider their magnetic properties and luminescent characteristics. Despite iron pyrite being non-magnetic, real gold has a unique property of reflecting infrared and the longer wavelengths of visible light very well, making it highly reflective even in the absence of direct light.

Note: It is worth mentioning that iron pyrite can still contain trace amounts of gold or be part of the surrounding matrix, but this is not a reliable method and is unlikely to be more than trace.

Final Thoughts

In summary, fool's gold, or iron pyrite, has distinct properties compared to real gold. Applying the tests mentioned above can help in distinguishing between the two. However, professional gemologists and metal experts often use more advanced techniques for accurate identification.