Pearl and Diamond Ring. Natural pearls, by their very nature, cannot be farmed or grown. Finding a natural pearl is a matter of luck, patience, and knowing where to look. An enormous number of natural pearls were formed by oysters in the Persian gulf, and historically this became the best-known source of them, ever since ancient times, but with the rise of cultured pearls combined with the depletion of oyster populations, the natural pearl is rarer than ever. This natural pearl is of a slightly flattened shape, known as a bouton (meaning ‘button’, in case you were wondering), and has a particularly attractive lustre, with a lovely even surface. Pearls owe their beautiful sheen to nacre, which is a substance secreted by oysters when an irritant enters their shell. It builds up layer upon layer, leading to a lustrous surface of unmatched beauty and complexity. Pearls have been prized for millennia, but there was a particular vogue for them at the opening of the 20th century, when paired with diamonds and platinum, they epitomised the delicate, sophisticated aesthetic of the ‘Belle Epoque’. With two charming antique cushion-shaped diamonds at its sides, this natural pearl ring would make a particularly refined addition to any jewellery lover’s collection.