Deep blue stones are very rare and expensive, and found only in Brazil. Aquamarines are also found in Africa, Pakistan, Russia and Afghanistan. The Most Expensive Aquamarine in the World The most ...

Spiny Oyster Shell is considered rare because it is only found in a limited geographic area and is only available in certain seasons. The Spiny Oyster itself is found in warm waters off the coasts ...

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 ...