Billed as the world's largest flawless Paraiba tourmaline, the 181.61-carat "Kat Florence Lumina" is expected to make a splash at Bonhams' auction on May 22 in Hong Kong. The journey of the Lumina began more than two decades ago in the rugged terrains of Mozambique’s Mavuco district, where famed gem hunter Don Kogen unearthed an […]