Na3Li3(AlF6)2 / Isometric - Hexoctahedral
The most powerful crystal in the top 100! Very interesting and rare crystal found in the same mine in Greenland as where Cryolite is found, similar makeup as well. It is more powerful then cryolite or any other crystal on the planet but frequency wise a little lower then Cryolite.
Cryolithionite fluoresces white to pale creamy white in SW and LW UV and briefly phosphoresces.