Infused crystal is a crafting component in The Witcher 3: Wild Hunt that can be dismantled into infused shard. It is needed to craft:
Crafting Requirements 
It can be purchased from the following merchants:
- All armorers and blacksmiths, except the one at Ardaiso Quarry
- Armors and weapons merchants in Nilfgaardian Army Group 'Center' Camp
- Merchant in the boatyard south of Refugees' Camp
- Merchant at Calveit Watchtower
- Merchant at Coast of Wrecks
- Merchant in Ursten
- Merchant by the road west of White Eagle Fort
- Merchant at the sawmill northeast of Rannvaig
- Merchant at the Isolated Hut on Hindarsfjall
- Merchant in Mohrin Village
- Merchant in Stacheier
- Ofieri merchant at Upper Mill
It is a random drop from base game monster nests starting at level 20, and select few monsters:
- Ice giants during Tedd Deireadh, The Final Age
- Ice troll in Clan Tordarroch Forge
- Golem at Olevald Clearing
In the Blood and Wine expansion, it is also often found during treasure hunts, and in many guarded treasures and bandit camps around Toussaint.
Tips
Infused crystals are required to craft infused slyzard hide, which are required for grandmaster witcher gear sets.
- Two infused dust can be used to craft an infused shard, and two infused shards can be used to craft an infused crystal.