Find the Alchemist's Mortar in order to unlock more crafting recipes. It's hidden in the Alchemist Tower in Lone Thistle, somewhere below the surface.

You've reached the Alchemist's tower! Search his basement to find his laboratory!

The door to the Alchemist's underground laboratory seems to be locked, but his Mortar should be inside. There must be some sort of hidden mechanism to open it somewhere in the tower.

The Alchemist writes about experiencing pain after activating the button which opens his laboratory door.

The Mortar was found inside the Alchemist's hidden laboratory behind a closed door. It should be returned to it's rightful owner. Placing the Mortar in the base will enable new crafting recipes.