What you see: A fancy intense green diamond that weighs 5.62 carats. Phillips estimates it at HK $22 million to $26 million, which is about $2.8 million to $3.3 million.
So, just how rare are green diamonds? “We know colored diamonds are quite rare compared to colorless diamonds, and green diamonds are particularly rare,” says Terry Chu, head of jewelry, Asia, senior director, at Phillips. “Blue diamonds are caused by the presence of boron in the diamond crystal structure. Green diamonds are not caused by any impurity. They’re caused by natural radiation–subtle energy that can change the diamond crystal to a green color if it penetrates it over a long span of time–millions of years. Very often, the radiation can only penetrate to the outer layer. Usually only the skin of the diamond crystal is green, and when the diamond cutter polishes it, the green will be gone.”
How rare is it to find a rough green diamond that reduces to a stone of more than five carats? “The finished product is 5.62 carats, so the original rock was maybe seven or eight carats,” she says, adding that in 15 years of experience in gem and jewelry auctions, this is the first green diamond of its kind that she has handled. “But I would not use five carats [as a benchmark]. I would say most green diamonds are below three carats. One other green diamond that was not even five and a half carats–it was 5.03 carats–made over $3 million per carat 18 months ago.” (It sold at Christie’s Hong Kong in May 2016.)
This stone is described as a “fancy intense” green diamond. What does that mean? “Fancy intense is a color grade given by the Gemological Institute of America, the most reputable laboratory in diamond grading,” she says. “When grading a colored diamond, it’s based on saturation, from faint to fancy vivid. Fancy intense is below fancy vivid, which is the most saturated. It’s one grade below fancy vivid.”
Why did the jeweler choose a cushion modified-cut for the green diamond? “It has a more balanced outline,” she says. “No matter which side or which angle you look at it [from], it’s a nice shape. It’s still a brilliant cut style, and brilliant cut styles make it more appealing. With diamonds in general, the round brilliant cut is most popular, and the most everlasting shape and cutting style.”
Why did you put the green diamond in a white gold ring? “When I saw this stone, I wanted to show the pure, real color,” she says. “White gold [allows] the best, most true presentation of the green color of the diamond.”
Is it comfortable to wear on your hand? “A diamond never looks too big on any woman,” she quips. “Don’t worry. One carat of diamond weighs about 0.2 grams. That means five carats equals one gram. It will never be too heavy or too big.”
This looks more like a mint green, or an ice green. Are there green diamonds that have more of an emerald color, or a spring green color? “It’s a pure green color. There’s no secondary color in the hue,” she says. “A yellow-green color is not pure green, and technically, an emerald green is a blue-green. It would not be a pure green. This diamond may look like a mint or an ice green, but those are not standardized technical terms.”
What is the green diamond like in person? “Throughout my career, every time I handle a rare stone, I always have a feeling of how amazing nature is,” Chu says. “When you explain what causes a green diamond, when you think about the whole process, you feel so small. A human being lives maybe 100 years. In a geological span, that is nothing. And the color–no mater how clever or technically advanced human beings are, we cannot duplicate the green color created in nature.”
Text is copyright Sheila Gibson Stoodley. Image is courtesy of Phillips.
Special shout-out to Aja Raden, author and green diamond fan extraordinaire.