While Elizabeth looks like she is holding clear plastic tubing, possibly to water the garden of flowers on her gown, it is widely acknowledged this item would have been painted with all the colours of the rainbow. So she is holding a rainbow in her hand, which I believe is actually quite a powerful statement. This symbol is most often said to represent peace and Elizabeth is then the keeper of peace. I agree with this assessment, but I feel like the rainbow may symbolize a little more.
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