A Great Ball is a type of Poké Ball categorized by the red and blue coloring on its upper lid. It has 1.5x the catch rate of a normal Poké Ball, and is good for catching higher level Pokémon that wouldn't be as easily caught with a normal Poké Ball.
Crafting
A Great Ball Disc is crafted by combining a cooked blue apricorn, a cooked red apricorn, and another cooked blue apricorn.
After using the disc with a Hammer and an Anvil, the resulting Great Ball Lid can be used to make the Great Ball.
Trivia
Great Balls used to be crafted differently. This recipe no longer works.