Millennials Rush to Buy Lab-Grown Diamonds. Millennials account for over $600 billion in annual spending in the United States. While GN Diamond speaks with over 2500 retailers on a weekly basis it hears more and more the surge in lab-grown diamond purchases among millennials. It is estimated that by the end of 2022, the lab-grown market may exceed $10 billion. Millennials are shopping for larger diamonds on a lower budget, concerned about resourcing and energy efficiency. Lab-grown diamonds certainly fill this need for these savvy shoppers, instoremag.com writes. Born between 1981 and 1996, millennials came of age alongside computers, digital technologies, and social media. These tech enthused shoppers love to research and purchase online, so it\u2019s crucial that diamond sellers can meet them in-store with technologically-advanced, interactive, online sales tools.