That mahoooosive necklace Camilla is wearing on the previous page - it's actually 2 necklaces worn together. One has 3 strands and one has 2.
It belonged to the QM and can be worn together or separately.
Incidentally there is a website called the Royal Order of Sartorial Splendour which is a fab daily fashion site for all Euro Royals. (orderofsplendor.blogspot.com)
And the woman who does that also runs The Queens Vault who updates all jewellery worn every day by both the Queen and Camilla. It is absolutely fabulous. (queensjewelvault.blogspot.com)