There are loads of people playing world of warcraft that will skill a certain profession and do not care to earn money from it. For example jewelcrafters : one of the skilling items you make will be the malachite pendant. necklace level 13, +2 agility.
Items you need : 1 malachite, 1 delicate copper wire (made from 2 copper bars)
1 copperbar is between 50 silver and 1 gold in the auctionhouse if the demand for copperbars is not extremely high, and 1 malachite is between 50 silver and 2 gold.
Total cost under normal circumstances 4 gold for 1 malachite pendant.
What do those jewelcrafters with their 15 malachite pendants ? They list them all for 2 to 3 gold each…. all 15 (depending on howmany they make to skill)
In most cases all wil be bid on (so no buyout) by enchanters that will disenchant them for the materials. Most people do not realise the malachite pendant is a popular item for rogues and hunters, especially for twinks. People that are making a twink do not have problems to pay a lot of gold as long as they get the best gear in the game for their level. So I list them at a maximum of 2 malachite pendants at a time for 30 gold.
And THEY DO SELL for that price. Also watch the trade channel. I saw somebody ask in trade for cobalt bars, good price blabla. Normally  1 cobalt bar sells for 5 to 8 gold on my server, so I put on 4 stacks of 5 bars priced 25 gold per bar (so 125 gold for 5, thats 500 gold per stack of 20 !!!) and THEY SOLD ALL. It was not the case that my bars were the only cobaltbars in the auctionhouse, there were a lot for 7-8 gold per bar in stacks of 20. Nevertheless my bars sold fo an insane amount.
When I prospect adamantite ore it happens sometime that I have 1 or 2 ores left. I sell them for 70 gold per ore and they also sell. Next time I try putting them in for 80 gold, 90 gold, 100 gold until they do not sell anymore.
Sometimes it will happen multiple people put an item for sale for low prices, like 5 people putting 15 malachite pendants in for 3 gold each. In that case just keep yours in storage and wait until the next day. If some people put it for sale cheaper than what you can make it for : buy them all and resell them.

So 2 important tips to make money :

1. Do not spam the market
2. Dare to overprice

I skilled my jewelcrafting up until I could prospect cobalt ore.

I bought a stack of 20 cobalt ore from the auction house and started prospecting.

Results :

So if you want to loose the money you earned by selling gems from prospecting adamantite ore this is a fast way to do it.

Prospecting cobalt ore : bad idea for gold.

I bought up a lot more Adamantite ore to prospect and also had my level 70 paladin Layah mine some Adamantite ore in Outland.

After prospecting I put some gems a bit higher on the auction house, and most of them sold within 5 minutes, so I put them in higher.

Guess what… they also sell for that price.

Deep Peridot : 50 gold each

Golden Draenite : 50 gold each

Azure Moonstone : 80 gold each

Adamantite Powder : 60 gold each.

What do you need : Jewelcrafting skill of at least 325


My rogue Tarjah has her JC at 325.

I bought for about 425 gold of Adamantite ore.

Thats about 110 ores (3.8 gold per ore)

After prospecting you get for every 5 ores 1 Adamantite powder.

I put them into 2 batches on the AH and sold the first batch for 39 gold each and the second batch for 40 gold each. The first batch sold withing an hour and the second batch sold within 15 minutes. If we take 40 gold for all of them (to get a round number) this means 40 * 22 = 880 gold (836 after AH fee).


Profit after prospecting : 400 gold.


With prospecting you also get gems that sell well on the AH like Shadow Draenite (30 gold each), Azure moonstone (50 gold each), Deep peridot (25 gold each), golden draenite (40 gold each) and some other gems, but those others do not seem to sell that well as the first mentioned. This means you can double or triple your gold by prospecting Adamintite ore. You could also prospect Fel Iron ore and get almost the same gems, but you will not get the adamantite powder.