Only Beatrix once made such an attempt when she swapped the diamond clusters in Queen Emma's Diamond (Star) tiara for ruby clusters taken from what I suspect was the Mellerio Ruby Parure or the Peacock Parure. Laurentien followed years later with only the central cluster replaced by a Ruby element but that created a cyclops look not to be repeated. And we have the example of the Emerald tiara being converted into an all diamond or diamond and pearl setting. Neither versions were big successes if you ask me. However. Using the diamond and emerald clusters in either the Mellerio or Begeer tiaras would be worth a try.