Transmutation is the skill of turning metalic aspects into more worthy ore nuggets. Most of the ore nuggets are not vanilla, and are part of Forge Dictionary mods. (For example, if you install IC2 and TC3, you could make copper transmutation.)
Basic Transmutation: (Required for any other transmutations to be researched) 1 Carus + 3 Metallum = 2 Gold Nuggets
Iron Transmutation: 2 Metallum = 2 Iron Nuggets
Copper Transmutation: 3 Metallum + 1 Victus = 3 Copper Nuggets
Tin Transmutation: 3 Metallum + 1 Vitreus = 3 Tin Nuggets
Silver Transmutation: 3 Metallum + 1 Permutatio = 3 Silver Nuggets
Lead Transmutation: 3 Metallum + 1 Vacuos = 3 Lead Nuggets