If a quest reward contains 1 skill book, I save before I turn in the quest and reload until I get at least 1 Malachite Gem. If the quest reward contains more than 1 skill book, I save/reload until I get 5 malachite Gems. You should also save/reload before approaching Malachite ores. Make sure you save at least 15-20 feet away from the ore.

I'd like to close by quoting Bellegar's famous last rhyme:

"Cursed be the mother that bred thee!
The wench must have been a hell-spawned banshee!"