Media playback is unsupported on your device

Rare Pink Star diamond 'to set auction record'

25 September 2013 Last updated at 17:28 BST

A flawless 59.6-carat pink diamond is to be auctioned in the Swiss city of Geneva at a record asking price of $60m (£38m).

Sotheby's David Bennett says the diamond belongs in "the ranks of the earth's greatest natural treasures".

Imogen Foulkes took a close look at the diamond.

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.