It was a gift from either Dagmar or Alexandra towards her sister Thyra Duchess of Cumberland. I posted a sort alike picture of the miniature of Alexandra in the Thyra and her daughters thread. Many imperial and royal gifts that have belonged to the Hannover family have been auctioned during a recent auction at I believe Sotheby's or Christie's. Main (Faberge) items came from Dagmar the empress (dowager) of Russia an her family, as gifts fore her sister's family. It really makes me sad to see al this royal historical items disappear around the world!
RN