Mission: https://www.wowhead.com/quest=27627/just-a-fancy-cockroach
In this mission he asks you to kill 4 types of amethyst, emerald, sapphire and turquoise beetles, but the first one is the amethyst:
https://www.wowhead.com/npc=46129/amethyst-scarab
It is not there, so you can not continue with...