Yellow diamonds get their color due to the existence of nitrogen molecules which absorb blue light. This impurity is also what gives orange diamonds their color.
Tiffany Yellow Diamond
The Tiffany Yellow Diamond is one of the largest yellow diamonds ever discovered; its carat weight is 287.42 carats (57.484 g) in the rough when discovered in 1878 in the Kimberley mine in South Africa, and was cut into a cushion shape of 128.54 carats (25.108 g) with 82 facets—24 more than a traditional round brilliant—to maximize its brilliance. It was purchased by Charles Lewis Tiffany for a total of $18.000
The rare 100.09ct fancy vivid yellow diamond, known as ‘The Graff Vivid Yellow’ was auctioned at $16.28mio at Sotheby’s Genève in May 2014.