3 Reasons Diablo 3 Gems show us the "Real" value of your Gold

It's been a few weeks since Blizzard gave us Diablo 3 players a chance to sell our piles of virtual dosh for some real world cash.

A lot more cash than what I have managed to earn selling Diablo 3 gold..

I've personally used this to unload 10 million gold for 25 Euro, which I was quite stoked about.
But when I tried repeating this success with another batch of 10 million gold I found that my auction did not sell, even after posting it three times in a row.

Naturally this is a direct consequence of Blizzard's institution of a minimum price on gold.
You are not allowed to sell your gold for any less than 2,5 Euro per million, which effectively prevents the normal mechanisms of supply and demand from working efficiently.

Charts make everything look more professional!

What is happening is that Blizzard has set a minimum price that is apparently higher than what the market is generally willing to pay compared to the massive amount of supply that is being offered at this price.
The result is that sellers throw their piles of gold in an increasingly bulging pile, while the buyers come in once in a while and take a few pieces from the heap.

But if 2,5 Euro per million Diablo 3 gold is not the "real" market value how can we find out what people are actually willing to pay?

This is where the gem market comes into play. Here are the reasons that gems are such a great tool for finding out what the "correct" value of gold is: