Etruria Marl Balls are dropped when mining Etruria Marl without a Silk Touch tool. They can be fired in a furnace to make Staffordshire Blue Bricks.
Etruria Marl Balls can be obtained by mining an Etruria Marl block with a tool that doesn't have Silk Touch. Doing so drops 4 Etruria Marl Balls.
Etruria Marl Balls can be fired in a furnace to make Staffordshire Blue Bricks.