At Arakas Druid Camp, search for an NPC called Dunikus Hornwind.
Say Work to him and he will tell you that he can make a Bluish Liquid if you bring him a pink leaf and an apple.
You can find Pink Tree's Leaf by killing Araf Kul and you can buy the Apple from Fali (Lighthaven potion seller) for 5 Gold Pieces.
When you collect them return to Dunikus Hornwind and talk to him. He will ask if you want him to make you the Bluish Liquid. Answer Yes and you will get it.
Gain:
Note: You can do this quest as many times as you want.