Ghost Iron Ore

Ghost Iron seems to be very plentiful in MOP, far more so than Obsidium was in Cataclysm.

Thus far, I've found the best spot (pre-90, at least) to mine this to be the northwest of the Valley of the Four Winds zone. There is a range of hills that runs N/S in that area, between The Heartland and Paoquan Hollow. Simply running loops around those hills and you can easily gather 10-15 stacks per hour, even just riding. There's a few enemy mobs at the edge of Paoquan Hollow, but otherwise it's free and clear and safe to mine, even at 85. There are also a lot of spawns within the rocky terraces of The Heartland that are worth checking out. I just tend to wander in those general areas and mining is plentiful.

I recently picked up a pair of [item=87213] which are definitely proving their worth - I didn't do any before/after analysis, but I am finding more nodes with them than I did without them.

You can get some extra Ghost Iron Ore per day without farming. There are some special type of seeds which provide crafting materials by planting and harvesting them at Sunsong Ranch (next to Tillers hub) in Valley of the Four Winds.

On harvest
[item=89233] provides Mote of Harmony.
[item=89197] provides Windwool Cloth.
[item=85216] provides random MoP herb. Could be any herb, even Golden Lotus.
[item=85217] provides random MoP enchant materials (mostly Spirit Dust).
[item=85215] provides random MoP minerals (mostly Ghost Iron Ore).
[item=89202] provides Mist-Touched Leather.

These seeds can be bought from [npc=58718] at Halfhill Market for a cost of 90 silver each. Note, you need to be Revered with [faction=1272] in order to buy them.

A useful macro for all ore (or herbs, for milling) :

#show Ghost Iron Ore
/cast Prospecting
/use Ghost Iron Ore

#show will show you the number of ore. If you have more than 5 ore and the macro generates an error, make sure the stacks are in multiples of 5. Also, it's possible to have several "/use [ore type]" lines in the same macro.

If you're in the habit of keeping a spreadsheet of your prospects and don't have an add-on, try this method:

1. 
   
2. Clear your bags of uncut gems.
3. 
   
4. Make macros for each gem (e.g. "#show Sunstone" or "#show Sun's Radiance"
5. 
   
6. Place the macros on your bar in the same order as in your spreadsheet.
7. 
   
8. Prospect and record the numbers shown on your macros.
9. 
   

This information is handy, in conjunction with knowledge of a) market prices of each gem and b) the cost of the ore (in time or money), for calculating how much the prospecting was worth.