All About Color Diamonds - Yellows

In the past few years, fancy color diamonds have experienced strong price appreciation, well above that of white diamonds. It seems that every few months, auction houses are reporting record prices for fancy color stones and they have quickly become an excellent complement to the portfolio of many investors.

In my continuing series, I will take a look at different colors in the fancy diamond color spectrum to see how they are formed, how they are valued in comparison to other diamonds, as well as take a look at some of the more famous diamonds throughout history in each color range, starting with fancy yellow diamonds, by far the most common fancy color.

Yellow in diamonds is caused by the presence of nitrogen within the stone that filters the blue/violet range of the visible light spectrum and reflects yellow. Since nitrogen is abundant in the Earth’s crust, it can frequently find its way into the diamond during the growth process. Some diamonds have been found to contain as much as 1% nitrogen by weight. Most nitrogen is incorporated into a diamond as a single atom, however it can exist at a molecular level as well. 

Nitrogen is so common in diamonds that the crystal itself is categorized based on the presence or lack of nitrogen. Common terms that we hear in the industry to describe diamonds are Type I or Type II. Type I diamonds contain nitrogen and account for 98% of all natural diamonds, while the much rarer Type II diamonds do not. 

Estimates suggest that around 60% of all fancy color diamonds mined each year are fancy yellow. However they are still extremely rare. Approximately 1 out of every 10,000 carats mined each year is a fancy color diamond. This means that 1 carat out of every 16,600 carats mined is a fancy yellow. And according to a 2005 study by GIA, only 6% of stones graded on the fancy yellow spectrum were Fancy Vivid Yellow, the strongest and most valuable shade. This implies that it takes over 275,000 carats mined to produce just 1 carat of fancy vivid yellow diamonds. And of course large diamonds would be exceptionally rare, possibly found only a few times a year, if at all. 

Yellow diamond color is graded on a somewhat different scale than other diamonds. Most fancy color diamonds have a 9-degree scale based on color saturation. With yellows, some of the lighter shades are graded on the lower part of the D-Z color scale (the one on which white diamonds are graded). The deeper yellows are graded on a five step color scale: Fancy light yellow, fancy yellow, intense yellow, deep yellow and vivid yellow.

Fancy yellow diamonds were historically found mostly in the Cape region of South Africa, however several diamond mines around the world produce yellow diamonds in some quantity. Yellow stones have been found more recently in some of the mines in the Kingdom of Lesotho as well. However the market for fancy yellow diamonds has been driven for years by the Ellendale Diamond mine in Western Australia. Until its closure in 2015, it accounted for nearly 50% of the world’s supply of fancy yellow diamonds. Since its closure, these diamonds have become much rarer.

Tiffany and Co. have long been associated with fancy yellow diamonds and had an exclusivity agreement to purchase Ellendale’s fancy yellow diamonds. Yellow diamonds have been part of the Tiffany identity since 1878, when founder Charles Lewis Tiffany bought a 287.42-carat fancy yellow rough stone. The rough stone was cut into a cushion-shape weighing 128.54 carats with 82 facets and was named the Tiffany Diamond.

The largest vivid yellow diamond ever found has had a somewhat more mysterious journey. Discovered in the Kimberly region of South Africa and first announced in March 2007, the stone would be named ‘The Sun of Africa.’ The finished gem weighed over 127 carats. However, the whereabouts of the diamond after it was finished are unknown, except perhaps to the buyer and seller. Hopefully this magnificent stone will reveal itself again in the future.

In 1977 a man named George Stepp of Arkansas found a vivid yellow diamond at the Crater of Diamonds State park. Crater of Diamonds is the world's only publicly-owned diamond site where visitors may search for diamonds and other gems and keep what they find, regardless of the value of the stone. The stone has remained uncut to this day and has become the unofficial symbol of the state. It was worn twice by Hillary Rodham Clinton during the inauguration of Bill Clinton, both as governor of Arkansas and as President of the United States. It was sold by Stepp to Stan Kahn of Kahn Jewelers who is still the owner of the diamond.

In 2011, I was fortunate enough to sell the Cora Sun Drop diamond. This 110 carat pear shape vivid fancy yellow diamond sold at auction for $12.4 million. The largest of its kind, it showed the phenomenal price performance of fancy color diamonds, which have continued to increase in value since. 

According to fancy color diamond traders Leibish & Co., vivid yellow diamonds have appreciated by 170% over the past 10 years. And unlike white stones that have shown considerable volatility in price over the last decade, fancy yellows tend to rise at a steady rate year after year.

The views expressed here are solely those of the author in his private capacity. No one should act upon any opinion or information in this website without consulting a professional qualified adviser.