I believe the stones have what's called an old European cut, which is considered an older brilliant cut from the 19th century.
--Previous Message-- : On Saturday in the weekly program 'Blauw : Bloed' (Blue Blood) the jewelry-expert : Martijn Akkerman (worked for the jeweller : Fabery de Jonge and works for the auction : houses Mak van Waay and Sotheby's) had a bit : of a clumsy and hard to follow explanation : for the fact that the most important jewels : were not seen yet. : : According to Mr Akkerman it had to do with : the cut of the diamonds (rose cut) which is : set in foil to reflect. Also the colour of : the largest diamond was a reason. In modern : times and lighting the desired effect will : not work. That is why "Máxima has only : worn brilliant cut diamonds". : : I am sure he was talking nonsense. Princess : Máxima has repeatedly worn the Bandeau and : according all information the large diamonds : in that Bandeau are rose-cut. I must say it : looked brilliant cut when the Princess wore : it on her way to the banquet in the : Rijksmuseum. The glitter and the splendour : was amazing, and that for rose-cut stones... : the explanation was so "not-Martijn : Akkerman", a bit clumsy, I am not used : to hear him making mistakes (again, assuming : that the Bandeau ís rose-cut indeed). : : : : :