Diamonds are forever?
Not in Mr Mellier's case. De Beers is a diamond miner based in South Africa, yet its new boss has never worked in South Africa, has no experience of the diamond trade and is new to the mining industry.
So what has he done?
He's spent almost his entire career working in the motor industry – he spent almost 20 years at Ford, invarious senior positions, and then moved to Renault. Latterly, Mr Mellier, a Frenchman, has been asenior executive at Alstom, thetransport specialist.
Is De Beers planning some sort of strategic change of direction?
No. Nicky Oppenheimer, the chairman of the company (and representative of his family, which owns 40 per cent of De Beers) reckons Mr Mellier will bring "fresh perspective". He and Anglo American, the miner that has 45 per cent of the business, also think the new boss's considerable project management experience will be a valuable transferable skill.
Why does De Beers need a new pair of eyes?
Well, the company is at an interesting point in its history. It has largely put its financial problems of a couple of years ago behind it, but it's no longer the world's largest producer of diamonds. New mines in Botswana are of growing importance for the company, and it's trying hard to crack sales in China.
How will Mr Mellier help?
Well, on the plus side, as his new employers say, he does have experience of big projects of the sort De Beers is pursuing in Botswana (and a degree from Insead, the top-notch business school). He's also used to dealing with governments, an important part of De Beers' business. Less happily, he hasn't always got on well with the Chinese – once calling for a ban on certain exports from there.
And will he be presiding over a stock market float?
That has been the gossip of late that De Beers might pursue an IPO. Still, the company is not even talking about such a prospect for now – and the Oppenheimers say they have no plans to reduce their stake.