A Glass Ball is an in-game item from Equivalent Exchange 3. You need this item to make a Minium Stone. You use it to craft a Minium stone by placing the Bell on the top of an Aludel. You will need fuel, Minium Dust, and an Inert Stone.
To make a Glass Bell, You need 7 Glass in a "n" shape (The first column, the third column and the middle at the top).