You can play Enchanting Arbitrage.

5x Spirit Dust = 1x Mysterious Essence
5x Mysterious Essence = 1x Ethereal Shard
5x Ethereal Essence = 1x Sha Crystal

Only a max skill Enchanter can combine the pieces.

Do an AH scan for current prices and for averages over time.
Weekend and weekday averages will vary.

If you can buy 5x Spirit Dust for less than 95% of the price of 1x Mysterious Essence, then you can combine them and sell for a profit.
Use the same formula for ME > ES and ES to SC.





You could try the tradeskill shuffle...

Buy/Farm ore.
Prospect it.

Green quality gems were cut and vendored.
Blue quality gems were cut and sold to players.

You have to option to make something, disenchant it, and use the mats to sell Scroll of Whatever.