He says that part of the reason the Marie Antoinette pearl is worth so much is because it's a natural pearl, which brings us to one quality that determines a pearl's value. Natural versus cultured.

Natural pearls are harder to find ... High-quality black opal can cost over $10,000 per carat, making it one of the world's most expensive gemstones. Over 90% of black opals come from Australia ...

Natural pearls vary in size ... Cutting the mantle: Stimulates nacre secretion. Cost Generally, less expensive due to controlled production processes. Typically, more expensive due to rarity ...

Throughout much of recorded history, a natural pearl necklace comprised ... a 16-inch strand of perhaps 50 pearls, often costs between $500 and $5,000. At the height of the Roman Empire, when ...

The star of the auction was Marie Antoinette's Pearl, a natural pearl and diamond pendant A pearl and diamond pendant that belonged to ill-fated French Queen Marie Antoinette has been sold for $ ...