Where can I gem farm?

I heard somebody in the one thread said he farmed gems for a week and then he bought himself a Tormented shield. Where might I be able to gem farm? I'm more looking to waiste my time getting the gems for armor than money, but I need to know where. Thanks if you can help me

Domain of Anguish

http://gw.gamewikis.org/wiki/Domain_of_Anguish

I think there is also a bit of a misunderstanding here.

You have on one hand rubies, sapphires and diamonds. These are rare crafting materials, usually acquired by either salvaging suitable items or as rewards for completing quests in the Vabbi region (quest->trade contract->ruby/sapphire/diamond). These are used to make armors.

The other thing are the Domain of Anguish gems. These are NOT materials but rather rare "collector" drops and can be exchanged for Tormented weapons. They are also worth quite a lot of money.

Do the mallyx the unyielding quest repeatedly.