(assuming he is willing...) Buckthorn easily finds the herbs to flavor the horsemeat, I mean, for Nar-Heru to use his "magic ritual".
The gem does not reveal its secrets.
(ooc: based on email) The wizard also spends some quality time for the book. He finds he likes spending more and more time with it. And it has changed....
(Tome: +2 item bonus to Knowledge checks (arcane, religion, or dungeoneering skills) involving shadow (nethrematic) or undead (necromantic) energy, places, creatures, users, etc. Can use to prepare Darklight (Encounter 6), Murderous twin (Encounter 7), and eventually Mirage Arcana (daily 9), Wall of Gloom (daily 10), and Blackening Pyre (Encounter 13) ALSO: choose one you can cast, can substitute in for a prepared spell, casting it instead. Note, there may be some technical difficulties adding to sheet, email me...).
ALSO: He also studies rituals in the book. And notices scrawled in the margins, while looking at one involving the retreiving of a chest stored far away:
RAKLEMESUOHFOTRAB