You mean a green gem in Order Realm?
The green gem is located in the green zone, the ruby gen in the red zone, the gold gem in the gold zone, the blue gem in the blue zome. All the people that hand them out are usually walking in the housing area but some around the housing area and I believe they have similar types of robes.
Also, the only portal to earth is in the Nexus

Dan, you need to get some sleep man your post was way screwed up. Good thing we know what your talking about.

green gem is located by the guy in the house next to the woman that gives you the quest lol