Martel Maides of St Peter Port, Guernsey offered a single-strand pearl necklace for sale with a £1500-2000 estimate on the assumption they were natural saltwater pearls – the highest bidder reserving the right to send them for laboratory testing prior to settling the bill.

Vendor and auctioneer will be hoping for positive results after the necklace, comprising 132 natural pearls, measuring from 8.5 to 9.5mm, took £110,000 at the sale on June 26.

A further selection of jewellery highlights appears in this week's ATG printed newspaper.