Astronomers suggest that there may be planets in our galaxy that are 'diamond' planets - hundreds of kilometers of 'thick diamond layers'.
It is history that americans bought land in moon at $21/acre, i think eBay should soon see some ads for diamond acres - guess lotsa marriage proposals will be now like 'will you marry me - and hand out a couple of acres of diamond planet' :-))
On a philosphical note - what value will be diamond be on a diamond planet ? will sand be mightily valuable on that planet ? what exactly is value ? - what people are willing to pay for something ? Hope some shrewd business minds dont get together to create artifically high value for some vague item and make all people go mad over it !