Magic price for Obsidium Ore

What a day!
I'm re-writing this post for the third time, keeping up with what's happening on my server... Don't run away! This is not a post about my server economy, I'll give you something that is true for everyone!
You all know that if you find [Saronite Ore] selling for something around 12g a stack you should buy it, since if you can't find a way to sell it for more (as a ore or in some other form) you can always smelt it and sell the bars to some vendor.
What is the price at which your buying [Obsidium Ore] without any fear of loosing money?
Well, most people didn't thought about this yet, since selling gems is already profitable, but the market is flooded with gems and on most server their value is going drastically down... So you may want to know at which price you can buy [Obsidium Ore] to prospect knowing that, no matter how bad the gem market goes, you're making a risk-free investment.
Well, this time the thing that fix the vendor price for [Obsidium Ore] is not smelting, but prospecting + cutting the uncommon gems. Uncommon gems can be sold to any vendor for 9g and you're guarantited to make at least 4 of them from any obsidium stack (and this if you're very unlucky). So the minimum gain you can make from a stack of [Obsidium Ore] is 36g, but you can surely buy safely a little higher than that... Let say 45g.

This was less than halfway through the process,
just 100-110 stacks (and yes, it's too much money
on my main, but I couldn't bother to send them to
my auctioneer alt)

Well, I began this post saying I'm quite busy on WoW right now... Why? Well, because since this morning people is consistently posting [Obsidium Ore] for less than 44g.
At the beginning I thought it was just some player anxious about selling his obsidium, but buying and buying (obviously leaving some of the cheaper stacks for perople undercutting automatically) I discovered that a player with a long name made by random characters had posted 200+ stacks at 44g.

What could I do? Obviously I instantly bought ~150 stacks and started prospecting them, then I stopped playing and went to study... What did I found 4 hours later? people where posting at 39g a stack! I bought some, had lunch, studied a bit more... And after 4 other hours it was gone to 34g for a single stack... And there where lots of them. Even with all the help addons can give you, prospecting 300+ stacks of [Obsidium Ore] and than taking care of the uncommon gems is a lot of work (or at least time spent not playing but watching your character crafting Jasper Rings and the like).
If I didn't knew that this was totally risk-free I could have bought less [Obsidium Ore], fearing the whole market was going down. But with this "seatbelt" I described you I could buy lots of [Obsidium Ore] without being worried about the result.
If you wonder what I'm doing with all that gems, you should read my post about What to do with Uncommon Gems and Making Gold in Early Cataclysm. Other than that I'm cutting a lot of Zephyrite, selling the "Perfect" that procs out of it on the AH, and the rest to the vendor... This is because [Zephyrite] is selling at 9g and 60s on my server, and at a very low rate... I wouldn't be able to sell it all. Luckly enough, I can burn a lot of gems making [Shadowspirit Diamond], otherwise I wouldn't have any place for them.

Remember that you're still in time to participate to the Best of the Month Carnival for the month of December! Entries will be accepted until January the 4th, so if you haven't already, go and check the rules.