All the posts here seem to be confusing the player-cast HP buff spell "Divine Glory" (big pink heart icon) with this potion effect.
The potion effect is 18-seconds of invulnerability. The potions come in certain Ping Potion Packs (related to the LoN game).
The HP buff spell (of the same name) is here:
https://everquest.allakhazam.com/db/spell.html?spell=1288