I was thinking the tourmaline cluster of the ring could be the second smaller brooch worn by Countesses Charlotte and Cynthia, but if the ring was indeed purchased in 1864 there apparently was another coloured-gemstone-diamond-cluster-brooch in the Spencers's possession. The National Portrait Gallery has a photo of Charlotte, Countess Spencer with a similar brooch pinned to her coiffure or headgear which is dated 1861.