Well, the
http://www.allakabor.com/eqatlas/crystalcaverns.html guide says "The Coldain will fight all the creatures in the zone, so you can use the Coldain as "guards" if you wish. The bad part about this is that they count the elemental illusions of enchanters as an enemy as well, and will attack them." and "The dwarves will attack all creatures that enter the area, including the orcs."
Couldn't find anything specifically about geonids perusing zam comments or 1999-2003 google searches.