Tanithria's Blue Dye

Source
This item can be found in Talismanic Textiles in Dalaran.

Tailoring

 * Basic Silkweave Robe
 * Handcrafted Silkweave Bag
 * Silkweave Hood Lining

As a quest objective
This item is an objective of the following quests:
 * Advanced Needlework
 * Sew Far, Sew Good
 * The Final Lesson?