The biggest, most expensive gemstones have always been popular throughout history, especially with royalty. Diamonds from India and South Africa, sapphires from Sri Lanka, rubies from Burma ...

Narrator: High-quality black opal can cost over $10,000 per carat, making it one of the world's most expensive gemstones. But mining black opal isn't easy. After investing tens of thousands of ...

Precious Metal Gems (PMGs ... high-end collecting and remain among the most coveted cards from the era. But what is it that makes these cards so valuable? Let’s take a closer look.