What is Fool’s Gold?

What is Fool’s Gold?

Almost everyone who has been panning for Gold or been hunting for minerals has found Fool’s Gold.

You will find small gold-shiny grains in your pan, and you are sure that you have made a fantastic find. When you examine it more closely, it turns out that it can easily be crushed by, for example, the tip of a knife (Gold does not crush, it flattens out), so it is not Gold.

What is Fool’s gold meaning?

In most cases, this “Gold” is Pyrite (sulfur silica), a brass-yellow, metallic mineral containing iron and sulfur and is a common sulfide mineral on earth. Fool’s Gold is one of the nicknames given to Pyrite. In German, there is a similar expression called “Katzen Gold”, and in French, it is called “l’or des fous”. 

Pyrit stone also known as Fool's Gold

Pyrit

Gold Nugget

GoldNugget

Chalcopyrite is Fool's Gold

Chalcopyrite

Pyrite, Chalcopyrite and Mica.

When we see it with the naked eye, it can (as its name suggests) look like little nuggets of Gold. Fool’s Gold thus has very different characteristics from those of Gold. The name Pyrite comes from the Greek word for fire (pyr) because it can strike sparks when struck against metal or stone.

How do I know it’s Gold or Fool’s Gold?

A couple of other minerals can also, under the right conditions, be confusingly similar to Gold. It’s Chalcopyrite and Mica. Mica that quickly falls apart can make it look like your Gold pan is full of small gold nuggets.

Gold Pan with Fool's Gold

Pyrite vs Gold

With some practice, you can use some simple tests to see the difference between Pyrite and Gold.

A little warning, though! Many gold nuggets have a collector’s value that is usually higher than the gold value. If you damage your Gold nugget with various tests, it can lower the value of your nugget.

The density ❗

The first thing that will help you identify if it is Gold is its density. Gold is three times denser than Pyrite, 5 for Pyrite against 19.3 for Gold. Typically, Gold stays last in your pan. 

Pyrite has a much lower density, slightly less dense than black sand. So the Pyrite should wash out with the rest of the gravels, but thin gold flakes can also wash out quickly, so be careful. 

Visual differences ❗

Both Pyrite and Gold are yellow, but Gold is less coppery than Pyrite. Also, Gold does not form cube-shaped crystals, as Pyrite often does. 

Most of the Gold nuggets encountered in the field are flakes or lumpy nuggets with rounded edges. It is possible to find gold flakes with sharp edges, which indicates a nearby source. But this is a rare scenario.

Streak test ❗

Gold will leave a yellow-Gold streak if rubbed against a piece of porcelain or white ceramic. Do the same with Pyrite, and it will leave a dark, greenish-black line.

Break and Moldability ❗

With a knife blade, a test is relatively easy to perform. Place your samples on a flat bottom (a pan, for example). Exert pressure with your knife on your pieces; Gold deforms under pressure, Pyrite will resist and break.

On the Mohs scale, which rates the hardness of minerals, Gold has a rating of 2.5 to 3. Pyrite is harder and is between 6 and 6.5 on the scale. 

The curious thing is that Pyrite can contain Gold, just like silver. However, it is only at such a low concentration that it can only be separated under special technical conditions.


Video about Fool's Gold

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