when you are doing the main part of the quest an you collect the 3 seeds for dragon statues, after the doors open an you go in, right before you talk to the big dragon guy, across from the locked chest that needs a key, there is a malachite ore node, it gave me 2 gems, theres also another node by the dragon behind a wagon hiden in the corner, didnt get any from it tho. also hear that the depleted ore mine has some at the bottom by the pedestals, not sure if i got them, ill check later... yep 2 nodes at very bottom one of them is hiden up to the right.
I also suggest saven them all until you get your named set of armor, Ulthring's allows for 2 enchantments on every piece, you can also get most if not all of your lvl 10 enchantments from the mage guy if you mind read him after closing all the portals in Aleroth, main quest.
http://divinity2.wikia.com/wiki/Malachite_Gemshttp://www.gamespot.com/xbox360/rpg...php?topic_id=m-1-53064460&pid=977060
