[Wyatt Hebert]

Well, let's do some analysis.

I may be wrong, but I do believe the formula is

Cost*(1-FB1)*(1-FB2)... etc... (round down)

So, you have 5*.5*.5*.8 (tho if that site is Construction bonus, it doesn't affect forging. There is a site for Forging bonus, tho, so I'll assume that's where you were.

That comes out to exactly 1.

So it should have cost 1 gem each. Now, if you had an inherent FB, that would drop it lower. However, my understanding of the process does not hold with your example.

I'll check more on my own, tho

Wyatt