Usually those spell name ingredients that are not specified as "Spell of X" in the list, are scrolls.
Try scribing a scroll of Silence and then try with it. :)
Oh, and I have been wanting to see such a staff for ages! Chakar is also good in infusing, so he could give it a shot after he is back from the excursion-incursions to the Deep.
That was indeed what it was, Chak. A scroll. Question answered. Thank you.
*one hand over his mouth but gives a big thumbs up with the other to everyone involved*