Sorry, Johan, which necklace do you call the "diamond pendant necklace"?
Though I would have liked it very much if Maxima had worn the laurel tiara or the ears-of-wheat tiara when she was a Crown Princess (or even now, when she is the Queen), I do not think it would have been the best option for the investiture ceremony. Though these tiaras are lovely, I expected something grander for the enthronement ceremony... and I was not disappointed!