Leafiara (prime)/Fun Facts Friday/Door 5
Using 325 Symbol of the Proselyte, clerics with appropriate lore training can use the Brimstone ability to turn any orb gem worth over 1000 silver into an explosive. These explosives are one use only, but can hit 1-7 enemies (increasing with orb value) with fire damage, including knockdowns. They can be used by non-clerics too after they're created.
This ability is largely ignored, probably because spending 1000+ silver to hit one enemy one time, ~2500ish silver to hit two enemies one time, etc. isn't exactly a strong value.
But one neat thing about it is that it has no RT, so if you're really badly in need of a knockdown followed by an immediate hit, then... well, it's an expensive option, but it is an option!
(And you can spam throwing Brimstones too.)