Did you know that? (Dominions trivia)

[Gregstrom]

Originally Posted by MaxWilson

...Forge of the Ancients counts BEFORE forge bonus? If the forge bonus came first, a 15% forge bonus on a 5 gem item would round down to 4 gems, and then Forge of the Ancients would halve that to 2 gems. Instead, Forge halves the cost from 5 to 2, and then a 15% bonus on top rounds down to 1.

It's also possible to forge items for free, if you can get the cost below 1. (It's almost never worth doing so, though.)

-Max

Did you know that... that's not the whole of it?

Site bonuses to Con are also applied independently of these two - I think the order is Forge->site->hammer. And... the gem cost appears to be rounded down between each step. So you can get Rings of Wizardry for 9S, or clams for 3W1N.