Yes...But the look is very similar to Camilla's snake necklace. Camilla may still get to use it when she became Princess Consort. The cigarette cae and the necklace is a good match. 
Get to use what? The cigarette case? What can she use it for when she doesn't smoke, or does she?
I can see now that the snake necklace Camilla wore with the durbar tiara, is different from Diana's necklace she wore with the black dress. But at first glance they
do look similar, from a distance.

That article posted by Emma,

I'm not sure if it is the one I am referring to, it looked something like that though.

But what I want to know now is, is Camilla wearing Diana's necklace in the above pic in the article? It looks like it to me, as the necklace Camilla is wearing does not look the same as the snake necklace? If she is wearing Diana's necklace I don't approve, however I do approve of her wearing Prince of Wales feathers jewellery, which obviously should be worn by the wife of the Prince of Wales.
Where exactly does Camilla's snake necklace come from? Mrs Keppel? Does it have a connection to Edward VII?