I messed up, and assumed that if the Depth Meter shows Underground, then I can farm gemtrees there. Turns out I need the background of undergrounds instead... What can I put there,
How to craft Emerald Staff in Terraria - YouTube
Terraria - EMERALD STAFF - Episode #6 - YouTube
Emerald Staff - Terraria Japan Wiki
Staff of Regrowth - Official Terraria Wiki
Weapons & Equip - Early-Game Mage and Summoner Changes and Additions | Terraria Community Forums
Magic weapon idea: Bejeweled staff : r/Terraria
Terraria Part #10 - Eyes on Me
The Optic Rod, an early pre-bosses summoner rod to make the class a little less painful. : r/Terraria