Fluorite

What a fabulous and well-priced specimen this is, a magnificent champaign-coloured Fluorite, probably from Blackdene mine, reputedly the oldest mine in Weardale dating back to the early 15th century and possibly before this.  This is even longer than I’ve been writing mineral descriptions.  I say “probably” because on the accompanying label, the mine name is set in square brackets, denoting a probable locality.  This is a David & Elizabeth Hacker label whose expertise on the minerals of Northern England is second to none.  I personally would have guessed Boltsburn mine, but who am I to disagree with the Hackers!  This large cabinet specimen is what you would term busy; a specimen which makes the eye dance between the incredibly gemmy champaign corners and crazed opaque, light biscuit tan face centres.  The first impression is that of many smaller cubic crystals, but this is an optical illusion caused by the patchwork of transparent and opaque zones.  The crystals are quite large, typically 3.5 to 4 cm on edge and because of the specimen’s size, many intergrown crystals are superbly displayed.  The gemmy corners, and they are indeed very gemmy, frequently display stunning rainbow colours.  Under LWUV it fluoresces intense Royal purple, especially along the gemmy to translucent edges, producing a frame-like effect.  Wow, what a fantastic [Blackdene] specimen.