This attribute defines how fast the item can mine blocks that are defined for the effectiveBlocks attribute or that are registered for the item's toolClass.
Some vanilla efficiencies:
| Item | Effieciency |
|---|---|
| Wooden Pickaxe | 2.0 |
| Stone Pickaxe | 4.0 |
| Iron Pickaxe | 6.0 |
| Diamond Pickaxe | 8.0 |
| Gold Pickaxe | 12.0 |