Grindstone (tool)

Grindstones (or sharpening stones) can increase of 20% the power of your weapon for 15 minutes. They can typically be found where there are blacksmiths or armorers, but the presence of these craftsmen is not strictly necessary.

Description
''Workbenches and sharpening stones can be found next to some smiths. You can use these to provide temporary boosts to their effectiveness. Workbenches and sharpening stones are indicated on your maps once you pass near them. This is where to go to get a boost before a tough fight.''