Elven whetstone is a crafting component in The Witcher 3: Wild Hunt that is needed to craft amateur's weapon repair kits. It is not needed for anything else nor can it be dismantled.
It can be purchased from the following merchants:
- All blacksmiths except the one at Ardaiso Quarry
- Bram in White Orchard
- Merchant at Calveit Watchtower
- Merchant in Lindenvale
- Merchant in Midcopse
- Merchant by the road west of White Eagle Fort
- Merchant at the Isolated Hut on Hindarsfjall
- Weapons merchant in Nilfgaardian Army Group 'Center' Camp
- Zoltan Chivay during The Battle of Kaer Morhen (dependent)
- Merchant in Stacheier
