Talent Crystals In Your World
Talent crystals are similar to rituals in that they are meant to be a way for GMs to add campaign-specific abilities or effects to a game, wholly separate from a character’s normal talents or abilities. You can also think of them as a way to grant specific spell-like abilities, albeit ones that always have a set caster level rather than varying with the user’s level or ability scores. Remember that talent crystals do not necessarily need to be focused on caster characters, either; a talent crystal with a strike talent, like the time splitter crystal, can be a great reward for a martial character! Players cannot obtain talent crystals normally, so their availability is set entirely by the GM.
For example, a PC might make a contract with a planar entity in order to be able to summon a certain type of minion for as long as they live. In that case, they might get a talent crystal that gives them a Conjuration companion with a specific set of traits. The power comes from the bargain itself, so they do not really know the power so much as they know how to activate it. Alternatively, a grand talent crystal could be an end-game reward that caps a character’s personal journey, granting them true access and mastery for a given sphere.
Similarly, an NPC might gain power far beyond their intended abilities, becoming much more dangerous as a result. Imagine a hot-headed young orc who gains the ability to throw CL 10th fireballs at-will, or a necromancer who can raise all the dead. Talent crystals can be the cause of a plot, rather than the reward, so do not be afraid to get creative!
If you want to make talent crystals more common in your world, consider allowing organizations access to knowledge for making specific, thematically-appropriate crystals. For example, perhaps a police force knows how to make CL 10th magic breaker crystals, making them extraordinarily effective at suppressing magic on the targets they hunt. Just remember not to drop a stash of these anywhere the players can reach!