The Enzalmed Skull of Kaiddor'Vec
Zalming is an ancient and generally outlawed practice of taking bones from spell-users and creating a spell focus from them. Most often, practitioners of this vile art take complete bones from fallen spell-casters (Mages, Clerics but any other is possible) and coating them in plaster just after their deaths. The idea being since magic never truly leaves the body, so it acts as a focus for spell-casters, giving a spell a +1 or to the DC of one of their spells once a day.
While this is generally the understood practice, stories tell of the ultimate instance of this magic when a renown magic user named Kaiddor began enzalming himself before their death. His family, the di Vec* clan were regognized artists and had vast fortunes from their work with royalty. There are various rumours about why he did this, the one most believed is that he was trying to change himself to lich in a unique fashion, enzalming himself while alive. Instead of taking his own life to complete the ritual, he was kidnapped by a group of dark cultists and executed, his head removed. Since he had already prepared himself, they they had a complete and powerful Enzalmed Spell-Head.
Mechanically it can either provide three additional spell levels of a caster's lowest spells they can cast per day, or it can provide +5 on spell focus for non-healing or fire related learning spells.
Cost: 10,000 gold pieces, Spell Level: As 7th level Caster
*di XXX is the designation of honoured families in any given area. Many have specific rights over non-honored families, including taxation and voting. Thus when he was alive, his recognized name would be Kaiddor of House Vec or Kaiddor di Vec in common usage. Stripping him of the recognition of the family is a significant embarrassment to him and potentially any offspring who could also lose these same rights.