The Jeweler in Diablo 4 handles all Gem crafting, socket management, Rune reforging, Mythic Unique target crafting, and Jewelry Caches. You can craft 7 gem types (Amethyst, Diamond, Emerald, Ruby, Sapphire, Skull, Topaz) across 5 quality levels using Gem Fragments and Gold. Salvaging returns 100% of Gem Fragments (but not Gold or Forgotten Souls). Unsocketing is free. Adding sockets requires materials based on gear type and item level. Grand gems (level 30) require 100,000 Gem Fragments, 30 Forgotten Souls, and 10M Gold.