Charoite is a relatively rare mineral that can only be found in Russia's Far East.
Within Russia, charoite is known as 'sirenevyi kamen', which means 'lilac stone'.
Charoite was initially discovered in 1948 but it was another twenty years before the site was revisited and further investigations carried out.
The area where it's found lies more than 600 miles from the nearest road.
Although charoite was named after the Chara River, it's not found in the immediate vicinity.
The Republic of Sakha restricts the amount of charoite that can be mined each year to 100 tons.
This is partly because of the location where it's found and also because there's only a limited amount of material available.
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