This trophy is titled "
Seeker of Sorcerous Knowledge" and the description is "Create the most valuable sorcerous item."
The item that needs to be created is an orb named Aether-in-Stasis and it is Fiore's ultimate weapon.
Save your game (so you can reload if you don't get the Item with your ingredients on hand) and then go to the Synthesis Menu and choose Manual Selection, select the first five boxes and switch to the Materials tab. Add five Ruby, Crystal, or Amber. Select the last box and switch to the Materials tab and select a Moonstone. The Quality will be 50 and the Impurities will be 16 with a result in Signeturgy. The Moonstone, and a quality of 50, are the only required element to obtaining the Aether-in-Stasis.
Synthesize until creating 'Aether-in-Stasis' and unlocking the trophy.
- Ruby can be farmed from several enemies during Chapters 3 through 6, from Lava Golems in the Trei'kuran Dunes starting from Chapter 9, and they can also be purchased from Ruddle upon completion of his quest.
- Crystal can be farmed from several enemies such as Damascus Fort in the Western Dakaav Tunnel and Dark Material in the Signesilica.
- Amber can be farmed from several enemies such as Stinger in the Resulian Plains, Gust Hornets in the Cathedral of Oblivion and the Maze of Tribulations, and Aquaregia on the Passage on the Cliffs and Coast of Minoz during Chapters 6 through 8.
- Gold can be farmed from several enemies and purchased from Santa in the Maze of Tribulations. It can also be synthesized with three Silver and two Alchemist's Water.
- Moonstones can be obtained in the Maze of Tribulations. They can be synthesized with five gold, or silver, and one Orichalcum. However, Orichalcum can only be obtained in the Maze of Tribulations.
Here is the unlocking image: