The designer had been selling at the Spirit of Christmas Fair at Olympia London (running from November 1-7 concurrently with The Winter Art & Antiques Fair).
The rings were stolen on the final day when the fair was closed and the stand was being packed up.
The diamond and sapphire rings and a pendant had been packed into a bag which was snatched from the stand.
In a statement the company said the rings were months of work for Nixon and her small team and the “theft is completely devastating”.
The team, who were attending their first major retail show since before the pandemic began, appealed for help using #findemilysrings on social media and alerted the police.
For all the images of the other missing items contact Emily Nixon on: firstname.lastname@example.org
Anyone with information should contact Crime Stoppers on 0800 555 111 or the police on 101 quoting Crime Reference Number 6025562/21.