The below tiara which is now in the keep of the Jewel house Bentley and Skinner is said to be possibly from the collection of Empress Eugenie of France but was sold on her exile to the UK to fund her lifestyle. So there is also plenty of jewels in the vaults of the jewel houses of which are not made public knowledge. I was also bowled by the other head pieces in this company's keep.

https://www.bentley-skinner.co.uk/london/jewellery/images/55264-an-archaeological-revival-coral-and-gold-spartan-diadem-18-500x500.jpg

Regards,

Dave.