Their beauty has captivated us for millennia. Their cost can be extraordinary–some are even considered priceless. Precious gems like diamonds, rubies, emeralds, opal, and jade are the ultimate treasures of the earth, and each one is made from a specific–and often torturous–recipe of chemistry, pressure, and heat. The secrets to their sparkle, color, and even strength lie deep inside the gems themselves, but could they also hold clues to one of the most enduring mysteries in the field of geology? From Tiffany’s workshop in New York to the sapphire mines of Sri Lanka, from North Carolina’s emerald fields to the jade-laden Forbidden City of China, join NOVA in the first episode of a 3-part series, "Treasures of the Earth," as we explore the fascinating science of gems.