Azerite Crystal

Azerite Crystals could drop from the following at the Twilight Shore and Nazj'vel in Darkshore:
 * Azerite Fury
 * Bubbling Azerite
 * Azerite-Infused Elementals
 * Darkshore Sentinels
 * Darnassian Archers
 * Druids of the Claw
 * Druids of the Talon
 * Orgrimmar Raider
 * Bilgewater Laborer
 * Dark Ranger

This item could also be collected from the following:
 * Small Azerite Deposits
 * Rich Azerite Deposits
 * Crates of Azerite
 * Azerite Crates

As a quest objective

 * The Azerite Stuff