From the soft blush of a fancy color pink to the icy brilliance of a D-grade white, the hue of a diamond not only determines its look but also its value and meaning. Thus, it’s only right to query how steadfast a diamond’s color is and whether it’s likely to change.
Does a diamond’s color fade over time? The short answer is no. Both natural diamonds and laboratory-grown diamonds (LGDs) are generally incredibly stable when it comes to color. That said, there are a few exceptions. Read on to discover more…
What color stability really means in diamonds
Color stability in a diamond refers to how well it retains its color. As a rule, a diamond’s shade is baked into its atomic structure and even after it’s been cut and polished, its color stays the same for life.
Certain types of lighting, different colored metals surrounding a diamond, and even dirt and grime can make a diamond’s color appear to have changed. But view it in different light, have it re-set or take it for a professional clean, and you’ll quickly breathe a sigh of relief.
Both natural diamonds and LGDs are highly stable when it comes to color, but let’s go deeper and really compare.
Natural diamond formation and color stability
Do you know how natural diamonds are formed? Around 4.5 billion years ago, stardust from the galaxy accumulated in the core of the Earth. It was this source of carbon that, when bonded under intense heat and pressure hundreds of kilometers deep, then crystallized and formed diamonds.
The origins of natural diamonds
These incredible gemstones were then brought to the planet’s surface by powerful volcanic eruptions millions of years ago and became lodged in pipe-like rocks. Even today, most are sadly buried far too deep for us to recover.
Why diamonds are so stable
Because natural diamonds are formed almost entirely from carbon atoms bonded together in a rigid tetrahedral structure, they are not only the hardest naturally occurring substance on Earth1 but also one of the most stable2.
How color forms in natural diamonds
The small amount of trace elements (such as nitrogen) or stress-induced irregularity in a diamond’s structure that cause coloration, is locked into place in normal conditions, making them super resistant to change. Generally, it would take extreme conditions (such as very high temperatures) to change the colors of a natural diamond.
The fascinating case of chameleon diamonds
But there are some exceptions, however. A ‘chameleon diamond’, a very rare type of natural diamond, is typically a gray-yellow-green color. However, when it’s heated to over 300° F or exposed to light after a prolonged period in the dark, it changes to yellow. This color change typically lasts around 15 minutes although some chameleon diamonds emit a yellow glow (or phosphoresce) for up to an hour3. Cool, right?
The science behind pink and argyle diamonds
Then there’s the mind-blowing science behind pink diamonds, particularly the coveted Argyle ones. These diamonds are photochromic, meaning their color can fade under UV light and reappear under visible or blue light. They are also thermochromic. Expose them to temperatures above a scorching 1,472°F and their color will take on a more purplish tone4. Also very cool.
Understanding diamond color grading
Color is one of the 4Cs of diamonds. The GIA’s diamond color scale is used to assess and certify the color (or, technically, the absence of color) in diamonds. For white diamonds, color is graded on an alphabetic scale from D to Z, starting at completely colorless gems and ranging all the way to those with a noticeable warm, yellowish tint. A diamond with any shade or depth of color beyond that is called a fancy color diamond – think vivid reds, pinks, blues, greens and browns, for example. Fancy colored natural diamonds are graded using a separate system that’s based on hue, tone and saturation.
Why a diamond’s color never changes
Because diamond color doesn’t change over time, once your diamond has been given its color grade, you can rest assured that it’ll stay that grade for life.
Lab-grown diamond production and color stability
Their name would suggest that lab-grown diamonds (LGDs) are meticulously created in sterile laboratories but, in most cases, they’re churned out in huge industrial manufacturing plants.
How lab-grown diamonds are made
And while LGDs have the same chemical and optical properties as natural diamonds, they’re created in an artificial environment in a much, much shorter timeframe. These controlled environments typically result in consistent gemstones that also have long-lasting color.
The two main methods of lab diamond production
Generally, there are two different methods of producing LGDs. One is High-Pressure, High-Temperature (HPHT), which attempts to recreate the extreme geological conditions required for natural diamonds to grow deep in the Earth, in a factory using powerful high-pressure presses.
What is chemical vapor deposition (CVD)?
The second technique is Chemical Vapor Deposition (CVD). This method involves heating carbon-bearing gases, such as methane, to extremely high temperatures in a vacuum chamber. The process breaks up the carbon-bearing molecules, allowing the carbon atoms to gradually build up layer by layer.
Color stability in lab-grown diamonds
Regardless of method, LGDs are generally as color stable as natural diamonds, since both types have stable atomic structures5. However, a subset of CVD pink-grey diamonds with high silicon content can behave a little differently. Much like Argyle pinks, these gems are subject to photochromic responses, shifting to a cooler, blue-ish tone when exposed to UV light.
Diamond color treatments and enhancements
It’s also worth noting that many CVD diamonds undergo HPHT post-growth treatment to remove brown hues, or irradiation and heating to create vivid fancy colors like pink, blue, or green. These treatments are permanent and can also be carried out on natural diamonds, so color origin testing is wise6.
Do diamonds actually change color over time?
No, under everyday conditions, neither natural nor LGDs change color. But, as we mentioned, sometimes diamonds can appear to have changed color due to external factors. These could include:
- A build-up of oils, lotions or grime that makes a white diamond appear dull, cloudy, or discolored
- Lighting changes that shift how a diamond reflects color or how the light travels through it
- Having a diamond re-set in a different colored metal. For example, a colorless diamond may appear creamier or yellow-tinted when set in yellow gold. Stick to silver, platinum or white gold settings if you want it to remain icy in color
- Certain diamond treatments or coatings that fade or wear off over time, though this is rare with high-quality gems from trusted sources. Again, check the origin of a diamond’s color before buying
If you’re thinking: “why does my diamond look cloudy?”, most often it just needs a good cleaning.
Why color stability still matters when choosing a diamond
Besides the few exceptions we’ve flagged, you can be reassured that your beautiful diamond won’t unexpectedly change color over time (even if, in very rare cases described above, it does shift temporarily after you have had a manicure, or you have been soaking up some rays on the beach).
Your natural diamond or LGD should absolutely stand the test of time in terms of both its dazzle and color.
Instead of worrying whether a diamond will retain its color in the years to come, focus your attention on finding one that fits your own unique style and story. When you do find it, be sure to show it plenty of TLC.
Sources
- https://pursuit.unimelb.edu.au/articles/diamonds-the-hard-facts/ ↩︎
- https://www.wtamu.edu/~cbaird/sq/2013/12/17/why-do-diamonds-last-forever/ ↩︎
- https://4cs.gia.edu/en-us/blog/colored-diamonds-mysterious-chameleon-diamonds/ ↩︎
- https://www.fcresearch.org/chromism-in-pink-diamonds-3/ ↩︎
- https://www.revediamonds.com/blog/do-lab-grown-diamonds-change-colour-over-time/ ↩︎
- https://www.gia.edu/gems-gemology/fall-2014-labnotes-irradiated-cvd-synthetic-diamond/ ↩︎
