Hello there!
Yesterday, I saw some Talasites on AH, so I bought them. One for 6 gold.
I made them into Steady Talasites, and sold for 22 gold.
10x 22=220
-10x 6=60
-------------
..........160G
I guess this can be done with other gems too.
And of course you can make this with shitload of gems, today I bought 20 of them, so I will get 320G.
It's basically because of the stone prices, and this cannot be done on server WITH Gem merchant on the Isle of Q.D. I guess.