Class : Elements
    Subclass : Metals
    Crystal system : Cubic
    Chemistry : (Au,Ag)
    Rarity : Uncommon

Electrum is the natural alloy of gold and silver, these two metals forming a complete solid solution. Although some authors restrict its use to terms comprising 20% to 80% silver, it is usually accepted as an argentiferous variety of gold. Electrum with a low silver content has a strong yellow color that becomes lighter as the amount of silver increases. Its density, close to 15 on average, is obviously a function of the proportions of the mixture. It may also contain traces of bismuth, iron, zinc, or copper. With the exception of placer flakes and nuggets, which consist of reprecipitated and naturally refined pure gold, hydrothermal gold extracted from mineral deposits is almost always electrum. This mineral takes its name from the Greek êlecktron (term which designated yellow amber). Electrum crystals are very rare (cubo-octahedra, octahedra, dodecahedra frequently hollowed out, flattened or rounded, reaching 2 cm) but are frequently twinned. Electrum occurs mainly in reticulated, dendritic assemblies or in very spectacular arborescences, in sheets and spongy masses. It is the main ore of gold.

Main photo : Electrum from Bucium, Alba County, Romania © Simone Citon

Frequently twinned on (111).

No fake listed for this mineral species.