Ores and mines
Opal from Thunder Eggs
Thunder Eggs provide a distinct weather-triggered route to Opal, a rare crafting material beyond routine ore-node mining.
Search the island after a thunderstorm for a Thunder Egg; use a pickaxe to break it when you specifically need Opal.
Repeat opportunistically when another Thunder Egg appears after storm activity. The egg spawn is rare and should not be treated as a fixed-yield renewable timer.
Stop once you have enough Opal for the planned craft; keep later Thunder Eggs intact unless more gems are required.
Open a guide to find other locations and see what the item is used for.
Thunder Eggs provide a distinct weather-triggered route to Opal, a rare crafting material beyond routine ore-node mining.