Ruby – Lab-made, Rough, Red

Rubies and sapphires are some of the most prized gemstones in the world and were also some of the first to be created in a laboratory. These synthetic corundum boules were grown by Auguste Verneuil and associates around 1900 (before he published his notes on his Verneuil process). Photo © Joel E. Arem, PhD, FGA. Used with permission.

Article: What is the Best Synthetic Corundum?

Credit: Joel E. Arem, PhD, FGA