Was informed needed to Kill the Croc prior to this Pristine Gem Golem spawning. While after an hour of just running over the Trap Spawn points per BreWall Maps I got it to finally spawn. So clear entire back zone area and then just continue to run over spawn trap points and eventually all "four" named that you need will spawn due to that. The timer is roughly 15-20 min but felt a lot quicker.
Glimmerstone, A perfect rock formation, shimmering gem sentry and a pristine gem golem.
Hope that helps!
ALso, if you don't have key but run to door and try and look thru, one of the golems will aggro you and then summon you thru door.