A new dark green species of mineral has been discovered by scientists examining a rock mined in Cornwall around 220 years ago.Kernowite, named after Kernow – the Cornish language word for the county – was found by a team at London’s Natural History Museum (NHM), led by Mike Rumsey.
The mineralogist said: “It’s amazing that in 2020 we are adding a new mineral.”Mr Rumsey added: “A lot of these discoveries happened over 100 years ago when the mines were still active.”So the discovery of a new mineral from Cornwall, particularly one that related to the regions most famous mineral, is really quite amazing.”
Mike Rumsey said the discovery ‘is really quite amazing’. Pic: Natural History Museum
The rock sample containing Kernowite was in the museum’s collection since 1964 but had been labelled as a loroconite mineral – a bright blue mineral also found in Cornwall.
The county is a world UNESCO heritage site – known around the world for new minerals.
Mr Rumsey made the discovery while analysing a rock taken from the Wheal Gorland mine located in St Day village.The mine was used between 1790 to 1909 but has now been demolished and replaced with a housing estate.Unless other samples are discovered elsewhere, the one example of Kernowite at the NHM and another in a private collection are the only known examples of the mineral in the world.
Rumsey’s team discovered Kernowite was a new species of mineral – and not liroconite. Pic: Natural History Museum
Mrs Rumsey said: “There is nothing left. It’s an extinct locality, we can never go back.”What we’ve got is a bit like a little time capsule.”The fact that this sample was preserved in a museum means that we can do this kind of research because we’d never be able to go back and collect anymore.”For hundreds of years, experts have thought green crystals were a variation of the liroconite mineral – but Mr Rumsey’s team found it has a different chemical makeup, and therefore can classify it as a different entity.The NHM’s principal curator of minerals said: “Liroconite is this beautiful, gorgeous bright blue mineral that comes from Cornwall and I was trying to understand why its colour varies from bright teal-blue all the way to a dark emerald green.”It turns out that the darkest green samples are sufficiently chemically different to the blue’s that we, as mineralogists, would define it as a new species.”Around 100 distinct minerals are discovered every year – and very rarely do they have large colourful crystals or are found in the UK.