Welcome to the RXP Gold Assistant’s Guide to selling Necklace of the Deep.
You can learn the pattern for this item from any Master Jewelcrafting Trainers in Outland. Most accessible are located in the Hellfire peninsula. Kalaen in Thrallmar for Horde, or Tatiana in Honor Hold for Alliance. Additionally, if you sided with Aldor you can also learn it from Hamanar in Shattrath City.
This item has a 2/3 demand rating, meaning it is a moderately sought after item.