Starting a new character is pretty annoying. One of the most annoying parts is re-learning every little thing. Every seed type and stone type, every cooking ingredient and crafting component. Even days after rolling a new character, it's so easy to lose track of what you don't know.
Sure, you can get a pile of items and have someone else teach you all about them one-by-one, but wouldn't it be just as effective to draw it out?
The blackboard or writing slate would be a furniture item that two Hearthlings use simultaneously. The first to interact with it stands at the board with a piece of chalk. The other watches. Slowly, the teacher begins to sketch and explain everything they know. I imagine this would take a long time for every object that has to be described. Maybe a mental inventory-taking phase before any learning can begin. And like Material Accounts, there could be no LP gain for this manner of discovery.
Slate and chalk aren't currently ingame, but slate is geologically similar to schist, and chalk is commonly found with flint. Perhaps these materials could be found by mining schist and flint, sort of like how cat gold is found.