A buyer’s guide to green diamonds

In brief: Stunning green diamonds are among the rarest and most highly-valued precious stones available in the market. Although green diamonds are obscured by the popular demand of blue and pink diamonds, they are actually rarer. In fact, only a handful of individuals can pride themselves in owning these mysterious rocks. Due to its rarity, naturally formed green diamonds come with a premium and synthetic green ones come as cheaper, conflict-free alternatives.

Unlike other colored diamonds, green diamonds offer a more unique story. When most colored diamonds are formed with “impurities” in their chemical makeup, the green color naturally comes out of the diamond when it is exposed to radiation. Worried? You shouldn’t be. This process takes places underground, during the diamond’s formation hundreds, thousands, or even millions of years ago, rendering them harmless and all the more intriguing today.

How does a diamond get its green color?Green diamond engagement ring with rose gold metal

As you probably know, diamonds are formed when organized carbon atoms are pressurized and bound together. A perfect, colorless diamond appears when it is chemically pure and structurally perfect. Most colored diamonds, on the other hand, are affected with “impurities” in the chemical bonding or “defects” in the crystalline structure. However, green diamonds are much more interesting. They acquire their color from an extremely rare process of natural irradiation.  Sometimes, the earth where the carbon deposits lie may contain highly radioactive material. A genuine green diamond endures a long history of exposure to atomic radioactivity during its formation underground, sometimes lasting for millions of years. The radiation, usually coming from radioactive uranium, has the ability to displace carbon atoms in the diamond from their positions and changes the rock’s ability to absorb and refract light, allowing it to reflect the green color on its surface. The longer it is exposed to radiation, the more vivid the green color becomes.

‘Isn’t radiation dangerous?’ you might ask. Radiation is dangerous but green diamonds are harmless. The green color does not contain harmful chemicals and is merely the green light being reflected on the crystal. Since the formation of diamonds takes up to millions of years, the stone only retains the radioactive stains and not the radioactive properties.

How are colored diamonds graded?

One of the aspects of grading a diamond is its color. When grading colorless diamonds, the value relies on the absence of color as colorless diamonds are chemically pure. The more transparent they are, the more valuable they become. However, an even rarer phenomenon occurs when a diamond that is usually made of carbon is affected with other chemicals such as boron in blue diamonds (read our complete guide on blue diamonds) or nitrogen in yellow diamonds (read our buyer's guide on yellow diamond), or is exposed to geological radiation as in the case of green diamonds. This makes it difficult to grade colored diamonds using the same criteria for colorless diamonds.

The Gemological Institute of America (GIA) has a special color-grading system for fancy colored diamonds, taking into account the hue, tone and saturation of the rocks. Hue refers to the primary color of the stone, the tint which appears on the surface (i.e., blue, red, green, yellow). Tone refers to how light or how dark the color is, with the faintest grade nearing transparency while the darkest leans to black. Saturation refers to how heavy the color appears on the stone. The more vivid, deeper colors are graded higher on the chart.

How to measure a green diamond’s intensity?

Green-colored diamonds can range from faint green to fancy deep green, the more vivid colors being the rarest. Pure green diamonds are graded as follows: Faint Green, Very Light Green, Light Green, Fancy Light Green, Fancy Green, Fancy Intense, Fancy Vivid, and Fancy Deep.

However, because green diamonds are less affected with impurities, it is often difficult to classify these diamonds according to color. More often, these diamonds produce a secondary color on its surface. The secondary colors can range from yellow, yellowish, blue, bluish, brown, brownish, gray, grayish, gray yellowish, and grayish yellowish. Because of its highly varied color scheme, green diamonds are symbols of various concepts, from peace and tranquility to growth and fertility.

You will find a vast array of green diamond with different intensities shown in the image below ranging from pure, yellowish, bluish and grayish hues.

green diamond’s intensity chart

Image taken from www.leibish.com

What makes green diamonds special for engagement rings?Green diamond engagement ring

Apart from its symbolism of abundance, the green color’s peaceful quality and ability to soothe the eye often associate the stone with safety, stability and endurance, and with good reason. A green diamond survives years and years of exposure to harmful radioactivity, and comes out as a rare and beautiful precious gem, made even more beautiful through the years by the combination of growth and suffering, nurture and struggle. What better symbol for enduring love?

Design-wise, green diamonds are very versatile. They may stand out on their own or compliment well with other colored stones like pink and yellow. With a wide array of colors to choose from, your loved one can select the perfect stone that would suit personality and taste.

Why choose green diamonds when other green stones are available?

First and foremost, diamonds are among the most durable stones in the world of precious gems. In fact, green diamonds are ranked 10 on the Mohs scale of hardness. Emeralds rank lower on the list at 7.5 - 8 and are less durable. Other green gems are farther down the scale with tourmaline at 7 -7.5 and peridot at  6.5-7 This makes it perfect for daily wear, such as on an engagement ring.

While some emeralds can be more expensive than transparent diamonds, they still lack that certain sparkle only diamonds produce. A diamond’s crystalline structure has the ability to refract light in a way that other gemstones cannot, allowing diamonds to exude a unique kind of brilliance. This is why other green stones like emeralds, peridots and tourmalines dull easier when they get dirty and will need more polishing, an activity that may lead to minimal scratching on the surface. Green diamonds may need polishing from time to time, but because they are more durable, they are more scratch-resistant.

In terms of value, as we have repeatedly mentioned, green diamonds are very rare. Diamond collectors may prefer the pure green diamonds which are rarer and come in higher prices. Green diamonds that have a secondary color, though less sought after by true collectors, are much rarer and are still more valuable than other green-colored gems. Most jewelers have never even seen one, whether it be natural or synthetic. Because green diamonds are extremely hard to come by, they are considered to be more exceptional.

Is there a more accessible alternative?Enhanced green diamond engagement ring

Yes. Artificially irradiated green diamonds are easier to find and are also less expensive. They are a great alternative to expensive natural green diamonds. Bear in mind that enhanced diamonds are not fake diamonds, as many shoppers erroneously believe. They are created by exposing an actual colorless diamond to certain treatments, which then causes the stone to acquire shades of green. This is why enhanced diamonds are not as cheap as some shoppers think they should be; they are real diamonds forced to acquire color through various treatments.

Make sure that you obtain a grading report from a reputable lab such as GIA or IGS when you buy a treated green diamond. This certificate will verify the origin of the stone. As we have mentioned, enhanced green diamonds are much cheaper than natural green diamonds, therefore ensure that you know the origin of the stone you are buying to avoid overpaying.

What are synthetic fancy-colored diamonds?

In the diamond family, green diamonds are among the rarest of fancy colored diamonds. However, popularity influences price and as the green diamond is less popular than blue and pink diamonds, they are cheaper on the list of other lab-grown colored diamonds. This makes green diamonds a great choice as they are rare but relatively cheaper.

As we have already discussed, naturally grown fancy-colored diamonds get their color from rare geological processes that occur during the diamonds’ formation. Synthetic diamonds, on the other hand, are grown in a lab in conditions that imitate the natural environment necessary to create a green diamond. The diamonds produced in this way are identical to natural green diamonds and it can be difficult to distinguish the two. The processes in which natural and synthetic colors are produced are so similar that most green diamonds are submitted to the GIA to test its “origin of color” before they are sold on the market. Even among lab-grown green diamonds, a fancy green color is still hard to come by, making each stone extra special.

One way to tell natural and synthetic diamonds apart is from the radiation stains on natural diamonds that appear as green or brown on the surface of the crystal. These stains cannot be copied in a simulated environment. As they appear only on the surface, they are easily removed through faceting and polishing, however polishers often leave the stains intentionally so that the stone is easily seen as natural.

Chameleon diamonds and other well-known green diamonds

Because green diamonds are so rare, only a handful of them are ever found. One of the most famous green diamonds is called The Ocean Dream. The name comes from its unique Fancy deep blue-green shade that resembles the crystalline image of a very, very deep ocean. The most famous green diamond is the Dresden Green. Weighing about 41 carats, the Dresden Green is the biggest known naturally-formed green diamond to have been discovered.

Another famous green diamond is The Chopard Chameleon. What makes the Chopard Chameleon and other chameleon diamonds unusual is their ability to change color to suit their environment. Chameleon diamonds are a variety of green diamonds that normally possess a green color but can change from brown to yellow, depending on light and heat exposure. When heated or kept in the dark, they can turn to bright yellow temporarily. As they cool down or are gradually exposed to light, they turn back to their original green hue. There is no exact explanation as to why this happens which goes to show green diamonds are not only beautiful, they are also mysterious and intriguing.

Photo courtesy for all photos: overstock.com