The Sponsorship Recognition Stone
The ball is able to spin, even with pressure on it, because of a 0.2 millimetre layer of water between the ball and its base. Solenoid-controlled jets pulse the water to keep the ball moving when no one is pushing it.
The stone
- is made from gabbro, a coarse crystalline basalt (often called Swedish ebony granite) from Transvaal, South Africa
- sits on a base stone of Indian Hassan green granite
- weighs 0.79 tonnes
- measures 82 centimetres in diameter
- was machined by the Kusser Granit company in Germany.