ok so i was farming the liquid rainbow in act 3 and i noticed that on every trip through the caves there was always atleast 1 resplendant chest on the 2nd level of the caverns of frost i think the other ice caves had them aswell.
ok so to farm it fast (takes me around 5-8 mins total) you load up a chapter thats in the late act 3 use the waypoint to goto The Bridge of Korsikk now once you arrive the cave spawns in one of 3 spots either top left, bottom left or bottom right if your lucky youll find it real quick the top level isnt very good loot wise you might get the odd yellow guy or blue group but mostly i run past it all.
once you reach level 2 its not a very big area but the chest is normally near the end not far from the stone that teleports you out of the dungeon.
its a really good place to farm especially if you have high MF theres normally special mobs around plus commonly i also find a treasure guardian down there and if your really lucky you will get the purple mob that drops the liquid rainbow.
also something noteworthy is the fields of slaughter (where the cave is located) also seems to had a high spawn rate of blue/yellow mobs so overall its a great place to farm stuff up.
for reference i have 108% MF and i average 3 yellow items per run plus a ton of blues. (i stop to kill any yellow/blue/purple mobs i see inside or outside the caves)