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Understanding Pink Diamonds
With only a few produced each year, pink diamonds are among the rarest gems on the planet. Whether delicately or intensely colored, these diamonds make stunning jewelry stones. Most of these gems are unearthed in Australia, where Argyle produces small but intensely colored pink diamonds. Other sources produce larger stones, though generally less intensely colored.
If you’re considering buying a pink diamond, read on to learn about the grading and quality factors for these gems. Fancy colored pink diamond buying considerations differ greatly from those of white diamonds.
Fancy Colored Pink Diamond Buying and the Four Cs
The IGS colored diamonds value listing has price guidelines for irradiated pink diamonds.
While cut is the most important value factor for colorless diamonds, color is the most important aspect for evaluating fancy colored diamonds. Hue, tone, and saturation constitute the three components of color.
Any pink diamond has a pink primary hue. However, diamonds with a pure pink hue are extremely rare and will command the highest prices of all pink diamonds. (Strictly speaking, pink is a light-toned red. However, gemological laboratories do certify pink as a hue in diamond).
Brown, orange, yellow, and purple secondary hues may be present in a pink diamond. The most common, brown secondary hues generally hold the least value. Attractive orange hues can beautifully complement rose gold. Still, those seeking a pink stone may find purple secondary hues the most desirable.
Tone describes how light or dark a gem appears. Very dark pink diamonds tend to have strong brown secondary hues and aren't highly saturated. Lighter tones of pink can be quite attractive, and medium tones can achieve higher saturation.
Few pink diamonds display high saturation. However, gems with very low saturation will appear brown or grey.
What Makes Color “Fancy”?
The Gemological Institute of America (GIA) grades color in colored diamonds differently from colorless or white diamonds. While colorless diamonds are graded based on their body color, colored diamonds receive grades based on their face-up color.
For gems very light in tone, pink diamonds may be faint, very light, or light. Darker tones can be fancy light, fancy, fancy intense, fancy vivid, fancy deep, or fancy dark. Grades of fancy vivid are the most highly saturated. Incredibly rare and highly attractive, fancy vivid stones are the most valuable pink diamonds.
The difference in price between fancy light and fancy is significant, but fancy intense pink diamonds have only a slightly higher per-carat price compared to fancy diamonds.
Because each grade encompasses a range of tone and saturation, be sure to look at the gem itself. Two fancy pink diamonds may have very different tone and saturation levels. The GIA’s colored diamond color reference chart shows examples of diamonds that fall in each of these categories.
The Argyle Scale
Argyle, the company that mines the majority of the world’s pink diamonds, has their own grading scale for assessing color in pink diamonds. Here, the hue is pink (P), purplish pink (PP), or pink rose (PR). A number then describes the intensity of color. For example, 1 is the most highly saturated; 9 is the most faint pink. (A "10" would be a colorless white diamond).
On this scale, a GIA fancy vivid or fancy deep would have a value of 1 to 3, fancy intense from 3 to 6, fancy from 6 to 7, and fancy light at 7. Light, very light, and faint stones are an 8 or 9 on the Argyle grading scale.
While clarity impacts pink diamond price much less than color, it can still make a difference. Inclusions are less visible in darker stones, and these rare gems are usually not eye clean. For pale pink diamonds, the higher the clarity, the more desirable.
The color of most diamonds arises from chemical impurities. However, unlike most diamonds, the color of pink diamonds arises from plastic deformation. This means that stresses on the crystal cause graining, which gives these diamonds their color. Pink diamonds with closely packed grains have deeper tone and more intense color. Some gems have an undesirable hazy appearance because of zoning, known as texture. Most importantly, if the zoning isn't observable in the face-up gem, then graining won't affect the stone’s clarity grade.
Although brilliant cuts don't showcase the gem’s color as nicely, traditional round brilliant cuts will sell at a premium compared to fancy shapes. On the other hand, modified fancy shapes are available at a discount.
Any pink diamond above 0.2 carats is considered large. Gems above one carat are exceptionally rare, and anything above two carats is extraordinary. Prices rise quickly with carat weight.
Type IA and Type IIA
You’ll frequently encounter the diamond descriptor, “type.” These scientific designations don’t directly correspond to the gem’s beauty. However, they do reflect rarity. Type I diamonds contain nitrogen in the carbon crystal structure, while Type II have no significant nitrogen. Type IA diamonds contain nitrogen in clusters rather than single atoms, as in Type IB. While both Type IIA and IIB lack any significant nitrogen,Type IIB diamonds contain boron, which gives them a blue or grey color. Pink diamonds may be either Type IA or Type IIA. Type II diamonds are rarer than Type I. Thus, they may sell at a slight premium.
Argyle pink diamonds are Type IA and fluoresce blue under ultraviolet light. Type IIA diamonds occur in other pink diamond locales, including India, Brazil, and parts of Africa. However, according to Argyle Diamond Investments, pink diamonds from other sources may temporarily lighten or fade in sunlight or heat.
Compared to diamonds from other sources, Argyle pink diamonds sell at higher prices and tend to be small but intensely colored. They often have secondary purple hues.
Some treatments can improve diamond color. Gemological laboratories can reliably detect them, and treated specimens generally exhibit very vibrant hues. Gems that have undergone treatment are available at a significantly lower price than untreated natural diamonds. Gemological testing routinely includes tests for treatments. The grade report will note any treatments.
High Pressure-High Temperature Treatment (HPHT)
Some inexpensive brown diamonds are put into a high pressure and high temperature (HPHT) environment, which alters the gem’s color. HPHT pink diamonds often retain a strong secondary brown hue.
While this process does increase the diamond’s price, it’s still heavily discounted compared to equivalent untreated pink diamonds. This is the most common type of treated pink diamond, and this permanent treatment won’t require further care.
Other diamonds received radiation treatments, which can produce pink colors. These diamonds may change color with extreme heat. Owners of an irradiated diamond should always inform their jeweler whenever the setting needs repair. Even a jeweler’s torch can alter the color of such gems.
Heating and cooling diamonds in a controlled environment can also produce pink diamonds. This process is sometimes performed after irradiation, but sometimes also on its own. As with radiation treatments, annealed diamonds can change color when heated. Keep these diamonds from strong heat sources.
Some diamonds may receive coatings to mask unattractive colors. Since coatings are susceptible to wear, buyers should be cautious when cleaning, polishing, or resetting a coated gem.
Synthetic Pink Diamonds
Laboratories can synthesize pink diamonds. Although available at a steep discount when compared to natural pink diamonds, these synthetics have little resale value. When purchasing a synthetic pink diamond, make sure the cut quality and clarity are good. Don't compromise on these factors for a synthetic stone.
Pink Diamond Simulants
A geologist, environmental engineer and Caltech graduate, Addison’s interest in the mesmerizing and beautiful results of earth’s geological processes began in her elementary school’s environmental club. When she isn’t writing about gems and minerals, Addison spends winters studying ancient climates in Iceland and summers hiking the Colorado Rockies.
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