Hugh Roberts, on page 122 in The Queen's Diamonds, refers to a hoop diamond necklace, now in the collection of Viscount Linkey, in the section on what we knew before as the Teck crescents tiara.
--Previous Message-- : Lord Linley sold part of his inheritance. He : and his sister did keep several of Princess : Margaret's jewels though. The Lotustiara, : the turquoise parure, the Snowdown tiara and : the Teck circle tiara/necklace all remain : with them. Im guessing that Lady Sarah has : the Snowdown tiara as it was her wedding : tiara and she's been seen wearing parts of : it as brooches. Considering that lady Linley : wore the Lotus tiara for her wedding it's : likely that piece has been inherited by Lord : Linley and still is his. That leaves the : Teck circle tiara/necklace and the turquoise : parure. Neither Lady Sarah nor Lady Linley : have been seen in them so who owns what is : unknown. Considering Lord Linley sold the : Poltimore tiara and the diamond necklace of : his mother im guessing the turquoise parure : is with lady Sarah and the Teck : necklace/tiara could be with either of the : late Princess' children. :