Large Brilliant Shard

Everyone comment how to get this by soloing some boring dungeons blablabla, but if you're a lazy person like me you gonna take another way to get this other than buying from AH, and there is!

Since 4.2 came everyone raiding or just doing heroics or even pvp must be overflow with JP's and honor's now you can make use of them except to buy 6 honor mount you can buy a pvp gear that cost 55honor like [item=16342] and de it, if you have [spell=83966] you'll earn more LBS occasionally.

Note: you can buy 250honor with 375JP

HF de-ing :)

If you are an enchanter and want to collect some Large Brilliant Shards, Blackrock Depths and the area before the entrace to the instance are excellent for doing this.

Go as if going to the entrance to BRD. You will go from the zone "The Molten Span" into a large inner cavern called "The Grinding Quarry". Walk towards the entrace to BRD and you will see a squarish pedestal on the floor ahead.

From here you will able to find "The Behemoth". He is a rare mob which has about 4,5k life and has been nerfed since his appearance. He will always drop the "Vilerend Slicer" a rare-quality main-hand fist weapon, which will always disenchant into a [Large Brilliant Shard]. He seems to have a rather quick respawn, about every 10 minutes. He is rather larger than any other of the mobs around, but if you can't locate him just try the following command: /tar The Behemoth, and you will be able to see quickly if he is about or not.

Make your way to the BRD instance.

On the way, if you have Tailoring as a profession, make sure you kill "Overmaster Pyron" as well. He is outside the insance and if a fire elemental so very easy to spot. He has a good chance of dropping Pattern: Cloak of Fire and occasionally [Elemental Fire] as well.

Once you have entered the instance you will see on you right an "Abandoned Mole Machine" *Thank Silvanas, that moles are forgetful!* Nowadays, BRD is much easier to navigate bacause you no longer need the Shadowforge Key to open gates and because of this lovely device which effectively can teleport you to another two areas of the instace without having walk too much.
You wil get two options: 1) "Just past the Grim Guzzler" or 2) "Into the Domicile". Choose the second one.

You will appear in a small room where and the "Abandoned Mole Machine" will be there. Come out, turn right and right again, and go down the stairs and straight ahead. You will find some mobs just outside the doorway as you go into a large open area called "Shadowforge City" with two terraces. You will be on the southern terrace and in the centre, below, you will see "Lord Incendius" and "The Black Anvil" - which is where a very devoted and patient blacksmith can craft the legendary Sulfuron Hammer.

You will see some other mobs infront of a doorway in the centre of the semi-circular terrace you are on. In the hall you will see some other mobs, and further ahead in "The Black Vault" you will find a boss and his pet: "Warder Stilgis" and "Vilek". You will get a Large Brilliant Shard from disenchanting what he drops.

Additionally, you can jump down kill "Lord Incendius" and disenchant what he drops.

Once you kill "Lord Incendius", go to the NE entrance and go up into the Hall of Crafting. You will find "Fineous Darkvire" walking around here. His drop will also dienchant into a [Large Brilliant Shard]. Again, if you can't spot him use: /tar Fineous Darkvire

Go back down and go SW past the "The Black Anvil", over the bridge and through the gap in the two large walls. Just follow the large walkway called "The Darkiron Highway". You will see lots of clusters of mobs, but you can easily avoid aggro as long as you don't walk to close to them. At the end of the walkway you find the boss "Bael'Gar". Kill and disenchant the drop - sometimes you will only get a Small Brilliant Shard from disenchanting his drops.

Now run back the way you came and on the right you will see a rather large opening with some mobs in front you. You can walk close to the wall and avoid aggro, but sometimes the demons there will pick up you scent and attack you, though this will not aggro the rest of the mobs. You will enter a cavern and right infront of you you will see a gate with a doorway. Walk to this, open it and you will be back at the entrance of BRD. Go out, find "The Behemoth", and repeat the process, you should be able to get a stack of these pretty quickly. Remember to reset the instance before you go back in.

"Long die Sylvanas!"

- Nhuvasarim, Die Todeskrallen.

This is the route I take for 100 shards per hour from BRD:

1. Set your hearthstone to the Iron Summit in the Searing Gorge.
2. Make your way to the entrance of BRD, checking for The Behemoth rare spawn in the underground quarry area before the instance portal for an extra shard.
3. Enter the instance and take the mole machine past the Grim Guzzler.
4. Kill Ambassador Flamelash.
5. Check for Panzor the Invincible rare spawn in the next room for an extra shard.
6. Continue onward and kill The Seven.
7. Continue down the ramp and through the doors into a large room and light the 2 braziers on the far side using the torches dropped by the Flame Keepers. The large door will open. Kill Magmus.
8. Continue and kill the final boss Emperor Dagran Thaurissan.
9. Hearth out and fly back to BRD. DO NOT RESET THE INSTANCE.
10. Enter BRD again and use the mole machine to go past the Grim Guzzler. Hop down to your left and kill Lord Incendius.
11. Head northeast through the doorway and kill Fineous Darkvire.
12. Keep going and kill Warder Stilgiss.
13. Use the Character Stuck feature in the help menu to kill yourself. Enter the instance to revive and then exit. Reset the instance and repeat.

Note: If you're quick enough, you will be able to use the stuck feature more than your hearthstone (even after killing Emperor Dagran Thaurissan). This ends up being much quicker because you avoid flying back to the instance the majority of the time.

I tested this for 5 hours and received ~100 shards every hour and never got locked out of the instance.

Enjoy!