Unlike our highly consistent round or heptagonal coins of today – these first coins looked more like irregular, flattened peanuts – but were minted quite strictly according to weight. The earliest electrum coins were discovered in Turkey and are dated to the 7 th Century BC, when they were traded in the ancient Kingdom of Lydia. This is probably why electrum was the first material used to make coins. It can get made in hot, pressurised environments, and it’s found readily in seams – often in or near gold deposits and close to the Earth’s surface.Įlectrum’s properties made it a highly valued resource in ancient times – it was found near the surface – so relatively easy to access, it was malleable – so easy to work with, and – in technical terms – looked very pretty. For anyone dying to know the specific shape of this – I’m sure you are – it’s commonly octahedral.Įlectrum is one of the few alloys that widely occurs in nature. Because their crystal structure and element sizes are so similar, they mix together very nicely, forming a stable alloy with an isometric crystal structure.
However, gold and silver don’t need to react with each other to form electrum – it’s not a compound, but a homogenous mixture of the elements. Being ‘noble’ means they are very resistant to oxidization and corrosion – this is because their d-subshells are completely filled with electrons, so the amount of energy needed to persuade them to react with something doesn’t crop up very often in nature. If you won a Nobel prize in chemistry, the medal would be made from gold plated electrum! This is quite fitting, as electrum’s parent elements, gold and silver, are themselves noble metals. Electrum is pretty versatile, you can cut it with a knife and – thanks to the trace metals – it can be an excellent conductor of electricity. Because there’s no exact formula, this means that electrum’s properties aren’t set in stone (or even metal).Īs you add more silver to the mix, the colour goes from lemony gold to near-white, the density drops and it becomes less resistant to weathering. To technically be called electrum the substance’s weight needs to be at least 20% silver, but it often contains trace amounts of other metals, like copper and platinum. This week Georgia Mills is going for gold, and silver, with a look at their malleable mixture – electrum.Įlectrum is a flashy name for a flashy substance – it’s what you get if you mix two of our most prized elements: Gold and silver.
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