Old Mine Cut Diamond SolitaireSimple and refined, the Jewels by Grace 18KYG 1. 85 ct. Old Mine Cut Diamond Solitaire showcases the enduring beauty of the old mine cut diamond. Made popular in the early 18th century, old mine cut diamonds were cut to offer superior sparkle in candlelight settings. This elegant ring is crafted in 18K yellow gold and features a 1. 85 ct. diamond. Part of the Jewels by Grace Collection, featuring extraordinary pieces sourced from around the globe.