I'd done a bit of Obsidium Shuffling off and on in Cata. 20 stacks of ore here, 30 there. But last night the legend I'd heard tell of from other bloggers happened. Tons of Obsidium Ore under 54g/stack. All told I bought about 400 stacks of Obsidium and shuffled for about 7 hours.
The sheer volume I was working in meant that no character could hold all the raw gems, but the image to the right, for inquiring minds, is what 157 stacks of Obsidium looks like in gem form! I invested roughly 14k into the ore and have so far made 10k from selling some of the blue jewelry and enchants, with about 30k more in inventory to move from the practice.
I always liked the idea of shuffling since, due to the nature of it, you have so many options. Though some are considered "the" way to go with them, if that market's crap, you can move on. Sure, Carnelian Spikes offer Greater essences; but if you're swimming in that, pair the gems with the now much more common Heartblossom and you've got Inferno Rubies!
I didn't really do this in bulk before so I had never really grasped how much time this took. Having done all of this, though, it's a ridiculous time investment. While it pays off in the end, it's not really a great tactic if you don't have tons of time to commit.
I really enjoy the shuffle a lot though; I love seeing the synergy between multiple professions working to turn something rather inexpensive into many times more gold. =D