Formula: Cu2Fe(AsO4)(OH)4.4H2O
Hydrated arsenate containing hydroxyl, forms a series with liroconite
Colour: Emerald green

Hydrothermal environments

Kernowite was approved in November 2020.


The type locality is Wheal Gorland, St Day, Cornwall, England, UK, where it was found by curator Mike Rumsey on a museum specimen that was collected 220 years ago. It occurred as large emerald-green crystals associated with liroconite. The mine was active between around 1790 and 1909, but it has been demolished now and there is a housing estate where the mine once was. Hopefully other samples will be found in other public and private collections, but until that happens the one sample held at the Natural History Museum London and another in a private collection are the only known examples of kernowite in the entire world (

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