Caster Amulets require: Magical Amulet + Ral Rune + 1 Perfect Amethyst + 1 Magical Jewel. Preset mods are 4-10% Regenerate Mana, +10-20 Mana, Faster Cast 5-10%.
Another example of a dual leech crafted amulet. Not a bad amulet for a Shape Shifting Druid with the +2 skills either.