The province of Huelva is world famous for other "fools". And in this case it is not the local people who are foolish, but the thousands of foreign prospectors who rushed to an unusual red-coloured river.
The river Tinto flows through one of the world's largest deposits of the mineral pyrite, which also has the name "fool's gold" or "oro de tontos" in Spanish.
Technically, "fool's gold" is known as iron sulfide containing a combination of sulphur with iron and copper. Due to its metallic shine, pyrite resembles gold and is often mistaken for the popular and beloved noble metal. It's no surprise then, that pyrite has always attracted people who think that all that glitters is gold.
However, gold and pyrite are vastly different minerals having in common only their shiny yellow colour.
However gold can occur inside pyrite as inclusions. One of the first skills that any gold prospector should learn is how to identify both gold and pyrite and thereby to avoid being considered as a fool.
Today pyrite is sometimes sold as a novelty item or used in costume jewellery.