"Monsters" That Drop the Stones

I spent a few hours farming strong and awful monsters in Iria today, with none of them dropping the stones. However, as soon as I switched back over to farming them in Uladh, the stones started dropping like candy. Is this yet one more difference between the "monsters" of the world? Would it be more accurate to add a little note stating that only Fomors can drop them? (I.E. mobs that also drop fomor scrolls) Or was this just a coincidence?

Solea Mobs drop them.

Also Mongeese

I only could fine one, off of a Capulet Family member in G14 Act 1 Scene 1. x.x I figured the drop rates were just insanely low...

The stone is dropped at a really low rate, I went to Courcle to grind off of lions for a lion claw lance and only got 2 stones.