Chatham grows emerald crystals in a secret lengthy process we invented 75 years ago. It takes about a year from start to finish: the crystals grow for about nine months. We start with a naturally mined seed of fine Colombian emerald with perfect color. We create a controlled environment rich in chromium to give our crystals a rich green hue. The crystals grow larger and cleaner than the emeralds grown in nature. When we cut the crystals, we cut away 80% of the rough to give you faceted emeralds that are essentially flawless in clarity and highly saturated in color. The price difference between the finest lab-grown and mined emerald of the same size and quality can be as much as $100,000 per carat!