Quills used for spell books must withstand strong magical currents, but also be magically inert unlike wandwood.
Conversation
Replying to
Lesser materials will crumble mid-spell and ruin the page, while wandwood will often apply the spell being written to the page under it.
Replying to
A Stylus of Bone is oft favored for its resilience. Knew a witch once who used a rough iron nail, said she didn't mind the burns.
1