Magic Mortar and Pestle (5e Equipment)
From D&D Wiki
Wondrous Item, rare
This mortar and pestle looks just like any other mortar and pestle unless gems of any kind are placed in it. When this happens, the mortar and pestle will illuminate a color corresponding to the gem placed in it and begin to grind it. Once the gem is ground into dust, the item stops illuminating, and as an action the user may inhale or ingest the dust to be healed 1 hit point for every 10 gp the gem is worth. The amount of time to grind a gem varies, relying on the value of the gem. Every 10 gp the gem is worth takes the mortar and pestle one minute to grind.