On October 7, Sotheby’s Hong Kong will offer one of the world’s most exquisite examples of grey-pearl jewelry for auction. A necklace and a pair of ear clips, known as the Cowdray Pearls, are estimated to fetch between $4.5 million and $7 million when offered as part of the Magnificent Jewels and Jadeite autumn sale at the Hong Kong Convention and Exhibition Centre. 

Culled from the collection of the English noblewoman and avid pearl collector Viscountess Cowdray (Lady Pearson), the necklace was hand-s…