Australian teacher Mia Pimentel was shocked to discover that her 1-carat diamond solitaire ring, originally valued at US$6,500, was worth only $350, a loss of roughly $6,150. The ring, which was lab-grown, had a significant impact on its resale value due to its design, craftsmanship and markup that don't carry over once it hits the resale market. Sydney-based master jeweler Ernesto Buono explained that advances in lab-generated diamonds have made them significantly cheaper to produce in recent years, driving resale values down fast. Many brides are now gravitating towards secondhand natural diamonds due to their staying power and smaller environmental footprint.