Koch, a natural pearl and diamond ring, early 20th century, set with a natural pearl measuring 6.8 -

Koch, a natural pearl and diamond ring, early 20th century, set with a natural pearl measuring 6.8 - 6.9 x 7.5mm, to shoulders millegrain-set with single-cut diamonds, mounted in platinum, size M, signed Koch, one diamond replaced, case

Accompanied by Gem & Pearl Laboratory report no. 24105, dated 31st December 2023, stating that the pear is natural saltwater.