a beautiful gemstone that's only found in Derbyshire in the UK!

This variety of fluorite is only found beneath Treak Cliff Hill in Derbyshire in the UK and a couple of years ago I had the opportunity to visit Treak Cliff Cavern where I had an amazing time. During our guided tour of the cavern, I saw a whole pillar of Blue John which was just stunning and some beautiful deposits but was disappointed I couldn’t manage to take any decent photos of them.

Back above ground they very kindly helped me have a go at polishing a piece of Blue John – my one and only attempt at lapidary. The family all enjoyed the café and museum (the delicious food kept them quiet while I was having so much fun).

Allegedly experts can identify which vein a piece of Blue John comes from by their patterning and colour but be careful where you purchase your stones - you may see Chinese banded fluorite being sold as Blue John. Remember that Blue John, like all fluorite, has a hardness of 4 and has poor stability (although this is improved by impregnating the stone with resin) so is best suited to necklaces, earrings and brooches where there is less likelihood of damage or wear.

We also saw this pair of incredible Blue John vases and this tazza in Chatsworth House... just wow...

Such an amazing gemstone…