The blood moor is also the best place to look for gem shrines, as several kinds of shrines cannot spawn there. Gem shrines still take longer to find than 3 flawless gems though.
To quote a post I made months ago after doing 17 hell blood moor runs:
There are always five shrines in the blood moor. There are no armor, combat, resist fire, resist cold, resist lightning, resist poison, mana, portal, or monster shrines. I didn't see any poison shrines, but I suspect they can appear in the blood moor, but are as rare as exploding shrines because they are so similar.