The Oppenheimer Blue sold on Wednesday for more than $57.5 million including fees at a Christie's auction in Geneva, making it the most expensive diamond ever sold.

The most expensive diamond in the world costs US $250 million.

The most valuable black opal features bright red stone against a very black base. In the '80s and '90s, gem-quality brown diamonds were worth about $1,500 per carat, but now many sell for up to $ ...

Aging sets, like those from the Diamond & Pearl era, are becoming increasingly desirable, but are very difficult to find. Trainers run the show with some of the most valuable Ultra Prism cards.