Soul Crystal
by WingofCootWondrous item, uncommon, rare, or very rare
A soul crystal is a mysterious crystal found deep beneath the surface in the Shadow Elves' Territories, which contains a measure of Radiance energy. A soul crystal can be used in place of a Radiance Focus to cast a spell with an "RF" component (though not spells with "R" component). Spells cast this way have a Radiance Bonus of +1 for an uncommon crystal, +2 for a rare crystal, or +3 for a very rare crystal; Glantrian nobility rank is irrelevant. This cannot be combined with the Radiance Bonus based on nobility rank/Radiance Focus location; a Radiance spell must be cast using either a soul crystal or a Radiance Focus, never both.
The Brotherhood of the Radiance (and even the Immortal Rad, at least as of 1000 AC) is unaware of Soul Crystals.
Shamans of Rafiel access the Radiance in a more limited, but safer, way. They may be either clerics of Rafiel or arcane spellcasters (bard, sorcerer, warlock, or wizard); must learn the Way of Rafiel (presumably from the existing Shamans). They must possess a Soul Crystal to use the Radiance.
They add the sunbeam, sickening radiance, call upon Radiance, and retain power spells to their spell list.