O gold it is a very precious metallic element due to some important properties it presents. This rare metal has a shiny appearance, a very beautiful golden color, is malleable, ductile and can be found in isolated form in nature. However, its main characteristic is its high chemical resistance, that is, it is inert, practically does not react with substances that could corrode it.
That's why gold has wide applications, including jewelry, decorations, utensils of great commercial value, fillings (because it is resistant to saliva), among others. Golden objects, such as the sarcophagi of the pharaoh's mummies, remain practically intact for a long time.
Native gold
Thus, gold is highly desired and has a high commercial value, but, over time, some imitations have emerged. Among them, the best known is the so-called "fools' gold"or"cat gold", a sulfur mineral called pyrite, which is the iron disulfide (FeS2). The name "pyrite" comes from the Greek pyr, which means "fire", probably because, when pyrite is hit with a hammer, sparks come out and because of its use in firearms such as the W
heellock.Pyrite's appearance, like color and shine, is very reminiscent of native gold and can deceive many beginners. But the similarities are just these, their other properties are totally different. For example, when heated, it gives off sulfur dioxide, which is a poisonous gas.
The distinct properties between gold and pyrite are used in tests to identify them. Here are the two main methods:
Pass electric current, as gold conducts electricity as does all metal, but pyrite does not;
bite lightly, if it is gold, the teeth mark will remain, for it is malleable; pyrite, on the other hand, is hard and brittle, as it is an ionic compound.
man biting gold
However, pyrite is not only meant to pass itself off as gold, it also has important applications. For example, from it, the sulfuric acid (H2ONLY4), which is the chemical substance most used in industries, so much so that the consumption per capita of it constitutes an important indicator of the technical development of the country. This mineral can also be converted to ferric sulfate, ferrous sulphate and iron oxides or as a source of sulfur itself.
In steel mills, pyrite can be used for the production of iron and, consequently, of the steel(Metallic iron alloy).
Pyrite is also confused with another mineral, Marcasite, which is a polymorph of pyrite, that is, both have the same chemical formula (FeS2), but their crystal structures are different. They have similar properties, but pyrite can be used to produce bracelets, necklaces, etc., while Marcasite cannot be used for this purpose because it turns to dust.
By Jennifer Fogaça
Graduated in Chemistry
Source: Brazil School - https://brasilescola.uol.com.br/quimica/ouro-dos-tolos.htm
