There are a few great jewelry sets in WAR, and The Great Oathstones are one of the best.

http://www.wardb.com/item.aspx?id=640114
http://www.wardb.com/item.aspx?id=640113

2 Pieces : On Hit 10% Debuff targets armor by 1200 for 10s.

As of 1.2.1 the missing Oathstone was added to the game. Initially there was much scrambling around to find the unlock for these two items, I’ve run at least 10 of my guildmates through collecting them on 4 seperate occasions. This will be a guide for both Order and Destruction, and the difficulty varying in a few different ways. For one, 4/5 of the unlocks are in Destruction territory and the Oathstone of Karaz-a-Karak is right near a Destro chapter hub. However, while the oathstone is nearby, Destro will need to kill a champion mob, whereas Order simply needs to talk to it. It takes a bit of a grind to get all 5 of the objectives done for this 2 piece set. On average it took about an hour solo (as Order), and about 2 hours with a group of 4. If you’re running a Destruction toon, you might have a bit of a challenege with the champ mob, but the rest of the pieces should be fairly easy, and close to your chapter hubs or warcamps.

I haz a map.

Red Square – For the unlock of Karaz-a-Karak (if you don’t already have it), you’ll need to make your way to Kadrin Valley. For Order, I recommend heading to the Warcamp in Thunder Mountain, Destro can use their warcamp in Kadrin Valley. Talk to or Kill Argnus Rockskull (58000,48000 in a small camp of dwarves). He is a R38 Champion last I checked, so Destro will need to bring their friends.

The next four locations are the drop items you need to collect for the Karak Eight Peaks Oathstone.
 
Green – The Nose is collected in The Badlands at 40k,37k and drops off the Bloodmaw Gnoblar. Most people report it dropping for them on the first kill.

Blue – The Trap Parts drop in Cinderfall at 54k, 54k off the Gnoblar Trapper. Typically you will collect this one the same time as the Tooth.

Orange – The Shiny Bits drop in Black Crag at 40k,11k off the Burnmaw Gnoblar. There is a Champion Ogre wandering around, be careful if solo.

Blue – The Tooth drops in Cinderfall at 54k, 54k from the Tooth Gnoblar.

Badlands can be accessed from either Warcamp. Order will have a good time running to the southern reaches of Cinderfall, and Destro will enjoy the roundabout they need to take for the Black Crag destination. All in all, the unlocks aren’t too difficult to get to drop, unless you’re Destro trying to solo the Champion. Good luck at that…

Once you collect all four of these items, you have to check and make sure you only have 1 of each. If you somehow picked up a duplicate of any of them, you have to destroy it! Right click on any one of the four pieces and you’ll recieve the unlock for the Oathstone of Karak Eight Peaks. Head to your capital city, find the Librarian, and purchase happily!
 
I have these ‘Stones on each of my r35+ toons, and they hit quite often. Methinks they’ll be nerfing the armor debuff sooner than later, so go out and grab em while ya can! Hope ya’ll enjoyed the guide! If you want to steal my map to repost elsewhere, leave me a comment of where it’s going, and a link where it ends up!