In WoW Classic, Mages have several unique class quests at their disposal. You can start the Level 50 Mage quest chain as a character of any race, and completing this chain allows you to choose one of the following items as a reward:
- Glacial Spike
- Arcane Crystal Pendant
- Fire Ruby
Magecraft
To start the final Mage class quest, simply talk to any Mage Trainer in any Capital City. They will offer you the following quest:
- Magecraft
This quest will send you to Azshara to talk to Sanath Lim-yo.
After you find Sanath Lim-yo and turn in the quest, talking to him a second time will give you the option to teleport to Archmage Xylem, who will give you the second quest in the chain:
- Magic Dust
This quest asks you to loot 10 Glittering Dust from Blood Elf Surveyors and Reclaimers in North-Eastern Azshara.
Once you've collected 10 dust, return to Archmage Xylem, who will also offer you the following quest:
- The Siren's Coral
Xylem will ask you to collect 6 Enchanted Coral from the corpses of Spitelash Sirens, which can be found in the Ruins of Eldarath and The Bay of Storms in Azshara.
Once you've accomplished this, return to Archmage Xylem one final time to receive the last quest in the chain:
- Destroy Morphaz
Your final task is to defeat Morphaz in the Sunken Temple and gather an Arcane Shard from his corpse.
Finally, return to Xylem, who will offer you your choice of the following rewards:
- Glacial Spike
- Arcane Crystal Pendant
- Fire Ruby
You should pick the Arcane Crystal Pendant here, without a shadow of a doubt, as the other items are much to weak to even consider.