Greater Planar Essences
Out of all level 70 materials these are the ones that I am always excited to get one of. Not only do I know I can sell it for 22 - 24g I know that I can sell it extremely fast. That is something I admire in an item. Being able to sell the item for the amount I want in less than an hour of putting it on the Auction House means I won't have a lot of extras piling up quickly and also while I am waiting for them to sell I can farm some more for booku cash. Now sometimes you will get undercut with Greater Planar Essences, mostly on the very rare day that they randomly stop selling. I've been cut down to 16g before, which is extremely rare but I jump at the opportunity to buy them all up and sell them when the market restarts.
The above picture demonstrates the average "good deal" on Greater Planar Essences that I see. I know for a fact that I can sell them for 24g if I really want to and 23g If I just want them to sell extremely quick. That is at least a 4g profit which is actually a lot better than some items that I buy and resell but to me it is a low profit. Depending on what time of day it is I will leave these items up on the Auction House as bait to try and get someone to undercut them further and then I will buy out that person's for maximum profit.
Picture of the "bait" working (Funny that it is my own friend at 16g. They're gonna be mad when I tell them I made a profit off their sales! =X
Only certain items are worth using "bait" on, Greater Planar Essences are ones that happen to qualify. As aforementioned selling Greater Planars is all about waiting. As always, patience will net you the biggest profit. Not always is there someone buying up mats to twink out a level 70 or to level through Enchanting. Just wait awhile and eventually someone will buy out the entire Auction House of them.
"Make" Greater Planar Essences
Now if you have an abundance of Netherweave Cloth and you are looking to get some more Greater Planar Essences and Arcane Dust you can make Netherweave Pants if you have access to Tailoring. If you don't have a Tailor yourself then you can get a Tailor to make these for you. Preferably a friend that owes you a favor because depending on how much Netherweave Cloth you have it could take awhile making them all into bolts and then making all the bolts into pants.
Below you can find the Netherweave Pants recipe and a bunch of information about it.
Bolt of Netherweave x 6 (30 Netherweave)
Rune Thread x 1
Result: 
Netherweave Pants
Now the reason you will want to make Netherweave Pants over anything else is because of their Disenchant table. Out of all the greens you can make with Tailoring, Netherweave Pants are the cheapest and have the best DE table. Below is a screenshot of the DE table you can find with Netherweave Pants.
Now even though that says the maximum Arcane Dust you can get is 4 I very commonly get 5 and that is without the Bountiful Bags perk. As far as Greater Planar Essences go I've never seen more than 2 and assume anything past that is impossible, unless of course you have the Bountiful Bags perk. Below are how much I can usually get per unit for both Arcane Dust, Greater Planar Essence and Large Prismatic Shard.
Arcane Dust (3g each)
Greater Planar Essence (24g each)
Large Prismatic Shard (4g each)
As you could have already guessed, Greater Planar Essences are the big money makers when it comes to Disenchanting Netherweave Pants and actually any level 70 green. With every green you usually have a chance to get 2 Greater Planar Essences which is close to a 50g profit from just a single item. Can't beat that! As with all level 70 materials the main place you will be getting them is through farming Botanica. Which actually works perfectly as a segway into my Botanica farming guide!
10k An Hour Botanica Farming Guide
Greater Planar Essences Video
Greater Planar Essence Tips
- Never unload Greater Planar Essences for less than you know what they go for because you have too many
- If you have an abundant amount of Netherweave Cloth you can make it into Netherweave Pants to Disenchant for a chance at some more Greater Planar Essences
- Even if you have a lot of Greater Planar Essences do not stop Disenchanting greens
- If there is a level 70 twink guild on your server enchant scrolls with high end level 70 enchants and try to sell them. Or directly offer to enchant the guild's gear.
Greater Planar Essence Math Page