Davo, that is a millions dollar question. I know there is an old...

Davo, that is a millions dollar question. I know there is an old pink of around 150cts polished or more aftrer that there was one a few years back around 60ct polished sold for $70mill, though was Vivid and sold at a record price. This stone is light pink, but the polishing techniques now are really good at enhancing the colour. It seems to have a few issues mainly to one side but a main stone around the 60ct is probable, possibly more assuming no cracks running into the heart of the stone.
A diamond like this is so rare it could go for anything, a lot will be determined from the planning software and any perceived risks.