Rare in both its vivid yellow color and its sheer size, the Cora Sun-Drop is the most expensive yellow diamond ever sold at auction. It was found in South Africa.
http://diamondland.be/cora-sun-drop-diamond-truly-unique-yellow-diamond/
sothebys
13 Of The Most Valuable Jewels In the World - 7th The Graff Pink Diamond
Educational1 CommentHow do you improve a 24.78 carat potentially flawless vivid pink diamond? Laurence Graff bought it at auction in 2010 for $46 million with a vision to make it even more beautiful.
https://www.naturallycolored.com/famous-diamonds/graff-pink-diamond