Lab Fluorite Faceted Loose Gems Blue Fluorescent Scintillator

These are loose calibrated faceted stones of blue glow lab fluorite, a wonderful mineral that is only rarely cut as gemstones.

Natural fluorite has an incredible range of colors, not just purple and green but reds, yellows, blues, and more.  On top of that, fluorite can have strong fluorescence.  In fact, it can be so strong that fluorescence is named after fluorite. 

This Europium-doped fluorite is grown for science - these crystals are valuable because they are extremely sensitive to many kinds of radiation (not just UV), so can be used as 'scintillators' for detecting the presence of x-rays.  Eu:Fluorite's glow is strong enough to change its color in direct sunlight, shifting from clear and colorless to a refreshing blue.  (So blue, that it can get too bright and overwhelms our digital camera, turning the photo purple!)

You might be wondering "why are fluorite gems is so rare when it's so cool?" That's because fluorite is a really tricky material to cut.  It has low Moh's hardness (rank 4 on the scale), and on top of that has four perfect cleavage planes - it wants to break into perfect octahedrons.  Combined with one of the lowest refractive indexes of any gem, it requires extreme care when cutting - any mistake, and the gem can split in half.

Still, I think the results speak for themselves - while these stones are a bit delicate (and not suitable for rings), the amazing glow is the brightest blue fluorescence I've seen from any stone, lab or natural.