Enchanting: Quality Has Its Price - Novigrad (Hearts of Stone)
Location: Upper Mill
Quest Giver: Runewright
Other Requirements: Hearts of Stone DLC
This quest is picked up immediately after completing the first quest, Enchanting: Start-up Costs from the same NPC. For this quest you will first need to collect a pick axe from a building nearby (it's marked on your map/compass) then go to one of three spots to collect Jade.
If you go to the top or bottom locations you'll not find enough Jade to collect - you have to go to the center most dot on your map, as shown in my screen shot below. You'll run into Arachnomorph enemies in this tunnel which are basically just big ass spiders. You'll find the Jade in the large room of the cave on the back side of the pillar. Use my compass screen shot below for better directions.
Once you've obtained the Jade you'll want to return to the Runecrafter in to give him the Jade and complete the quest. Now all you have to do is pay him an assload of money to unlock the final two craft levels for his profession. The first investment will be 10,000 Crowns while the second is 15,000 Crowns.
Both are very well worth the investment as this tradeskill allows you to be extremely over powered. Below are three of my favorite enchants from the Runecrafter:
Preservation: Allows the weapon sharpening tables buffs to last until Meditating
Severance: Increases the range of Whirl
Protection: Automatically gain a Quen Shield when entering combat