Camilla has already worn this necklace a few times in the past years, always on official trips overseas (India and Middle-East)... and always with a matching turquoise blouse!
October 5th, 2010, in Jodhpur, India:
March 14, 2013 in Doha, Qatar:
March 15, 2013 in Riyahd, Saudi Arabia:
November 6th, 2013 in Dehradun, India:
November 5th, 2016 in Muscat, Oman:
And here, not a good view of the necklace, but a good view of Camilla's earrings and engagement ring: