Looks like all gems are nerfed in current update build in Testlive forums. While we don't have all numbers yet, it's like +dmg gems nerfed to 40-70%, and invuln gems to 60-80%.

Source

Gems stacking isn't nerfed yet, but early gearing players got owned to a legendary level.

HAHAHAAHAHA, i knew it wasnt rly worth investing time on crafted armour:D

though it still might be abit better then most gear.

seems they nerfing all gear though.. this brings too light the promise of"gear not meaning much in pvp", but i wonder how this effects pve...... oOoOoOoO

some good knews.. but it dosnt change the fact theirs no pvp content working yet, and Yahkmars still bugged, hope those come soon because thats whats gonna stop ppl leaving.(funcom has lost tons of subscribers, its hard to miss)- dont think any of us are tempted too stay much longer, were just hopeing they turn it all around and make AoC the amazing mmo that it can potentially be, or at least a sign they are moveing forward in strides, and not a crawl.

+8 damage gems nerfed to +0.5 - personally I'm laughing my cute little arse off.

The whines and cries in OOC have been fabulous. That's a -94% reduction. Spiffing.
Hope it stays at that. Now all these cheap cunts who have been 2-button IWIN pvping will have to l2p. My heart fucking bleeds for them.

There is still nothing to do in that game.