Go back around 572 million years, to Precambrian times, and the Earth was a very different place. Hundreds of millions of years before dinosaurs had evolved, if you went to the Anti-Atlas Mountains of Morocco you would have found a scene of earth tremors and volcanic eruptions.
It was in this geological activity that Africa’s largest silver ore deposit was created at Imiter. Warm water, rich in dissolved chemical elements, circulated through cracks in the rocks, depositing silver and other minerals in veins and cavities.
Silver that occurs naturally in the elemental state is called native silver and it is metallic pinkish-white. There are other minerals on this piece of native silver too. It is partly coated with silvery grey argentite. Both native silver and argentite are important ores of the silver used by silversmiths.
But that’s not all! This specimen has another mineral treasure only visible under a microscope. Tiny grey needle-like crystals of mercury silver sulphide form a very rare mineral called imiterite.
In 2013, while the Oxford University Museum of Natural History is closed to have the roof fixed, some of the exhibits have sneaked away to the town centre!
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