Cube

The RuneScape Wiki also has an article on: rsw:Cube

Cube
Released							4 January 2006 (Update)
Members							Yes
Quest item							No
Properties
Tradeable							No
Equipable							No
Stackable							No
Destroy							Drop
Examine							A yellow cube.
Values
Value							0 coins
Alchemy							Not alchemisable
Weight							0.001 kg
Advanced data
Item ID							6899

Cubes are items used in the enchantment room in the Mage Training Arena. They, like Icosahedrons, pentamids, and cylinders, can be turned into orbs used to obtain points in the minigame. If one leaves the enchantment room, it will disappear from their inventory.