Calaverite (gold telluride)
Collection Highlights | Updated 4 years ago
Gold most commonly occurs as a native metal, but will form compounds (or minerals) with tellurium, sulfur or selenium.
The gold-bearing minerals that contain tellurium are called ‘tellurides’. The Golden Mile deposit in Kalgoorlie, Western Australia, is a massive deposit containing greater than 1500 tonnes of gold.
Some 70 to 75% of gold in the deposit occurs as native gold, but a further 20% occurs as tellurides. The remaining 5 to 10% is in the form of 'invisible' gold that has substituted into the crystal structures of various minerals or occurs as minute particles.
Therefore, extracting gold from telluride minerals, such as calaverite, which contains around 42% gold, has been very important in the history of Kalgoorlie mining, producing around 300 tonnes of gold.
Gold-bearing tellurides were first identified in the Golden Mile deposits in May 1896, three years after the first discovery of gold. Prior to 1896, rocks containing tellurides were not recognised as rich gold ores, looking somewhat like pyrite (or fool’s gold)-bearing waste, and were discarded, strewn on cart tracks and walkways, and also used as building stone. For a short time the streets of Kalgoorlie-Boulder had indeed been paved with gold!