Strontium Titanate Rough (Fabulite)

These are facet rough of lab created strontium titanate, a classic labmade stone that used to be sold under several names, including "tausonite" and "fabulite".  

SrTiO3 has extremely high dispersion (0.190), which is over four times that of diamond!  

In practical terms that means it has incredible fire - it briefly was attempted as a diamond imitation, but the stones had too many rainbows and were obviously something different.

It only has two downsides: its relatively low hardness of 5.5ish, (suitable for pendant usage) and how difficult it is to get these days.

Strontium titanate is used as substrates for chips, and as a diaelectric material in ultra-high-voltage capacitors.