Description

Blue John Fluorite Slice – Derbyshire, England

This beautiful polished slice is genuine Blue John Fluorite from the Blue John Cavern at Castleton in Derbyshire’s Peak District.

Blue John is a distinctive banded variety of Fluorite (calcium fluoride, CaF₂), famous for its layers of purple, blue, white and yellow. It is associated particularly with the limestone around Castleton, where the coloured Fluorite occurs in veins and nodular formations within the Carboniferous Limestone.

This individual slice displays beautiful natural bands of purple-blue, creamy white and warm yellow Fluorite. Polishing the stone reveals the internal patterning particularly well, making each slice completely individual.

This is the exact Blue John slice you will receive.

Weight: 269g
Origin: Blue John Cavern, Castleton, Derbyshire, England
Mineral: Fluorite – calcium fluoride (CaF₂)
Display stand: Included

Where did the name Blue John come from?

The origin of the name isn’t known with certainty. One story suggests that it developed from the French bleu-jaune, meaning “blue-yellow”, referring to the colours found within the stone. When we visited the Blue John Cavern ourselves, our guide shared this as one possible explanation for the name.

Other historical explanations have also been proposed, so bleu-jaune is best regarded as part of the story and folklore surrounding this unusual British mineral rather than a confirmed origin.

A remarkable British mineral

Blue John has been worked as an ornamental stone for centuries, with its striking banding making it particularly suited to polished slices, jewellery and decorative objects.

Modern extraction around Castleton is carried out on a very small scale, and workable material is carefully removed from the surrounding limestone. The Blue John Cavern itself contains eight of the fifteen traditionally recognised veins of Blue John.

Use the video to take a closer look at the colour, translucency and natural banding of this individual specimen.

https://youtu.be/CxGeVxBVqm4

 

Curious about Fluorite? Discover the story of our unusual Green Opalised Fluorite mystery sphere and see just how varied this remarkable mineral can be.