“Diamonds are forever—forever and ever.” As the camera pans, the transparent diamond’s meticulously cut facets refract light in a dazzling display. Even decades later, people still love to use diamonds as a symbol of their deepest hopes: for marital bliss and the purity of new life. Though the actual effects remain unknown, that hasn’t stopped people from cherishing this tiny, translucent, incredibly hard, and outrageously expensive gem.

However, you might not know that diamonds aren't all transparent. Green diamonds are a special type of colored diamond. While most colored diamonds get their hues from the different trace elements they contain, green diamonds acquire their color through radiation from uranium deposits beneath the Earth's surface.

The color of green stone

The typical colors are eight in number: pale green, light pale green, light green, soft pastel green, medium pastel green, rich pastel green, vivid green, and deep rich green. Among these eight colors, the further a color is toward the end, the higher its value and the more expensive it is.

How much does a green diamond cost per carat?

A truly natural, pure green diamond is extremely rare, because most green diamonds owe their color to radiation. As a result, the surface color of these diamonds cannot withstand cutting without being worn away, making it easy for them to lose their original hue and thus affecting their value. Consequently, a pure green diamond commands an exceptionally high price—often exceeding one million yuan even for a one-carat stone, rather than just hundreds of thousands.

The largest and most famous is the Dresdner Green Diamond, weighing 40.70 carats. The Dresdner Green Diamond is a 41-carat, internally flawless colored diamond with a brilliant, translucent apple-green hue that makes it truly exceptional.

The World-Famous Green Diamond, the Dresden

Another famous green diamond is the "Ocean Dream," the only diamond certified by the Gemological Institute of America (GIA) as having a deep blue-green color. It was mined in South Africa and subsequently cut and polished into a 25-carat cushion-cut diamond that is virtually flawless inside. In 1998, it was set into a ring.

Green diamonds rarely appear at jewelry auctions. In 2009, Sotheby’s Geneva auctioned a vivid green diamond weighing 2.52 carats—the largest vivid green diamond ever to appear at auction, according to the company’s records. The diamond was set in a ring and sold for US$3.52 million.

Appreciating the Green Diamond

Synthetic green diamond

Nowadays, many artificially synthesized green diamonds have appeared on the market; however, their value is far lower than that of natural green diamonds. In the laboratory, the radiation method used to synthesize green diamonds can not only turn colorless diamonds into green ones but also transform yellow diamonds into green diamonds through radiation.

Since the type of radiation used in the laboratory is hardly distinguishable from natural radiation, even professional gemological research institutes may not be able to accurately determine whether a stone’s color is artificial or natural at this time.

Natural green diamonds typically exhibit green or brownish surface spots known as "radiation spots," which cannot be replicated in a laboratory. These radiation spots are located on the diamond's surface and are usually removed during the gemstone faceting process—this is precisely why light-green or green diamonds often lose most of their green hue after cutting. In certain cases, however, cutters may choose to leave the radiation spots near the girdle intact in order to preserve some of the green color.

Artificially treated green diamonds typically exhibit a uniformly green color throughout.

However, sometimes green occurs beneath the surface of cut diamonds; its color distribution is uneven and may manifest as color zoning depending on the facet orientation. Only in very rare cases do naturally colored green diamonds exhibit a uniform green or blue-green body color.