British artists Damien Hirst diamond-encrusted skull artwork has sold for its $100 million (GBP50 million) asking price. The stunning piece includes 8601 diamonds - one of which is worth $8 million (GBP4 million) - has been bought by an un-named investment group. As a condition of the sale, the skull - which cost $24 million (GBP12 million) - must embark on a global tour of museums and art galleries. Hirst was crowned the world's most expensive living artist in June (07) when his contemporary work "Lullaby Spring" sold for $19.2 million (GBP9.6 million).