It's called price gouging. In case you don't know what it means, Wikipedia to the rescue: Price gouging is a pejorative term referring to a situation in which a seller prices goods or commodities much higher than is considered reasonable or fair.
I'm aware of what price gouging is, I'm more interested in demonstrating a cause and effect sequence to FEU. I was spending about $200.00 a month on this game during chapter 4 to gear my toon, whom I enjoy playing. With the new chapter coming out shortly, and the very marginal increases provided by the level 72 gear (which is missing all of the major stats mages are after- crit, mattk and int)- I have little reason to spend anything to begin with. Level 75 will probably see me opening my wallet again, but if- and only if- prices are dropped to a reasonable rate. And I'm sorry, but nearly $5.00 per extraction stone isn't that.
It boggles the mind, really, that they increased the price this much the day D3 was released. Another gear-grinder that will cost far less in terms of real-world cash to play and succeed at.