LSO Gem Rough, Blue Fluorescent Glow in the Dark Scintillator Crystal

This is facet rough of LSO (Lutetium Oxyorthosilicate), close cousin to LYSO (Lutetium Yttrium Oxyorthosilicate).  All show bright blue fluorescence strong enough to give them a full color change to light blue in direct sunlight.  They also have a mild afterglow, showing a blue glow after exposure to UV which can be seen in cupped hands.  Note that LSO reacts much more strongly to 365 nm UV, and 395nm will be much less effective.

LSO is a very unusual crystal grown for use in science and industry.  It has a clear base and very strong blue fluorescence. It glows incredibly bright under UV light as well as higher energy radiation, and because of this it can be used to detect invisible gamma rays, xrays and even alpha rays.  Given how expensive lutetium is LSO has been largely supplanted by LYSO, where less expensive yttrium substitutes in.  The main differences are that LSO is more dense and tends to be more phosphorescent. Its fluorescence is so strong it has a striking blue glow in sunlight--this effectively gives it a color change effect, since it looks colorless under room lighting and light purple-blue outdoors. It has a very interesting and unique look which you can't find anywhere else.  Based on the density and fluorescence characteristics we believe this is either endmember LSO, or has only a small amount of yttrium mixed in.

Asianometry on youtube recently made a cool video about this material which you can watch here https://www.youtube.com/watch?v=XpYYGiUX0x0

LSO is not very hard at around 5.8, just under tanzanite, and as such is not a good choice for a ring, though it would be great in a pendant or earrings.