I was finishing up my cuatro colinas missions when I got to one that said to harvest a diamond. Since I still had to harvest 3 of the ibex species in order to get "The Slam of Glory" achievement, I figured I would hunt ibex. I initially got a diamond ronda ibex but it did not complete the quest. After that, I decided to try again go for the beceite ibex but once again it did not register as me completing the quest. Finally, I went for my final Gredos ibex in order to at least get the achievement. Like the other 2, this one did not register as me completing the quest, but it also did not give me the achievement either.
#Cuatro Colinas Broken Diamonds
grim reef
clever meadow
I can confirm that I'm having trouble with this achievement as well. Here are the diamonds I have. I did read somewhere that someone got it from just harvesting and not selecting taxidermy. I've only done one like that so far and working on the other three to see if that triggers it.
