Some of the world's most expensive necklaces have sold for mind-boggling prices over the years. Some haven't sold at all - mainly because they are just so incredibly pricey. These high-end, ultra-expensive necklaces typically include multiple diamonds with eye-popping carat weights, but some also use other rare jewels, including rubies and sapphires. Read on to learn about some of the most expensive necklaces ever.

Garrard's Heart of the Kingdom Ruby or De Beers' Marie Antoinette Necklace? Click through to find out.

What is the most expensive necklace? Is it