I think the shorter one is the 34 diamond bequest to Queen Mary from Lady Mount Stephen - which was auctioned - and the longer is the one worn by Lady Sarah - but I am hopeless at identifying these things in pics.
In volume I produced by Christies it says Giana Tufnell had been Lady-in-Waiting to Princess Mary Adelaide, Duchess of Teck, the mother of Queen Mary, and Giana became the second wife of George Stephen, who became The Baron Mount Stephen of Mount Stephen, British Columbia and Brocket Hall, Hertfordshire.
--Previous Message-- : : Princess Margaret certainly had more than : one stunning diamond rivière.