Stone
Snowstone shards that absorb the contents of any book read while holding one — a library in a pebble, first used to cure Alurra's blindness.
Library Stones are shards of Sevendori snowstone enchanted by Minalan to act as living archives. A reader holding a Library Stone transfers the contents of whatever book they read into the stone, and anyone who subsequently holds that stone can access the same text directly. They are introduced in Court Wizard, when Minalan gives a pouch of them to Pentandra:
They're from Sevendor, the Spellmonger's home. He calls them 'Library Stones'. When you read a book while holding one, the information in the book is transferred to the stone, where anyone who uses it subsequently can read it. At least, that's how I understand it. I was planning on testing it on Alurra when we were attacked at the palace.Pentandra, Court Wizard
Old Antimei uses the larger of the two stones Minalan provided to address Alurra's blindness — a use-case that spreads: Library Stones become the standard teaching tool for blind magi across the Magelaw.