Pink, Red, and Purple Diamonds

Pink and red diamonds are particularly important because, in the vast majority of cases, their color does not result from a simple chemical impurity. It is a record of the crystal’s deformation history.

This makes them one of the best examples of how geology, crystal defects, and cutting combine to create perceived color.

The Most Common Natural Pink System: the Band Around 550 nm

The vast majority of natural pink diamonds display a broad absorption band at approximately 550 nm.

This band is strongly associated with plastic deformation and colored lamellae within the crystal. However, despite decades of research, the complete atomic configuration responsible for this most common pink absorption has not yet been conclusively established.

The precise formulation is therefore:

The 550 nm band is associated with plastic deformation and is the principal cause of color in the vast majority of natural pink diamonds.

An overly strong formulation would be:

“A single, precisely identified atom is known to cause all natural pink diamonds.”

[VISUAL 35.1: Plastic deformation, {111} lamellae, and the broad 550 nm absorption band in a natural pink diamond]

Pink Graining and Colored Lamellae

In many natural pink, purple, red, and brown diamonds, color is concentrated in narrow parallel zones.

These may be described as:

• pink graining;
• brown graining;
• colored deformation lamellae.

These zones are not surface scratches and are not necessarily fractures. They reflect a change in the crystal lattice associated with deformation.

During cutting, the rough can be oriented so that reflections of these zones produce a more even and stronger face-up pink.

A relatively small physical volume of intensely colored material can therefore have a major visual effect.

Type Ia and Type IIa Pink Diamonds

Pink color is not limited to one atomic type.

Natural deformation-related pink diamonds may belong to types I and II. Nitrogen-related centers can additionally modify the spectrum and appearance, but diamond type itself is neither a color grade nor a sufficient test of natural origin.

In some type IIa diamonds, the deformation-related pink system can exist without measurable nitrogen in the usual FTIR sense, further demonstrating that nitrogen is not a necessary component of the unidentified 550 nm center itself.

Rare Natural NV Pink Diamonds

There is a small, exceptionally rare group of natural pink diamonds in which NV⁰ and NV⁻ centers produce the primary color.

Such stones have sometimes been called “Golconda pink” in the literature, but the term is problematic if interpreted geographically. The physical type of color does not prove that a stone came from the historic Indian mines of Golconda.

NV centers are especially important because they are also very common in:

• treated natural diamonds;
• CVD laboratory-grown diamonds;
• some HPHT laboratory-grown and subsequently treated materials.

Thus, NV pink is not synonymous with natural pink.

Research snapshot—GIA database 2008–2016, published in 2018/2019 and presented again in 2025.
GIA’s large study collected data on more than 90,000 natural diamonds in the pink–purple–red–brown continuum submitted from 2008 to 2016, and a representative subset of 1,000 samples underwent additional spectroscopic analysis. GIA’s research summary states that approximately 99.5% of natural pink diamonds owe their color to the deformation-related system with broad absorption around 550 nm, while natural NV pink is very rare; the same conclusion was presented again in a 2025 GIA technical presentation. This is a result from a large GIA submission population, not a universal share of world production.

[VISUAL 35.2: Natural deformation-related pink versus rare natural NV pink and treated/laboratory-grown NV pink]

Red Color

Red diamonds occupy a narrow and extremely rare part of the pink–red space.

In many natural Fancy red diamonds, the underlying mechanism remains associated with an intense 550 nm deformation system, with additional absorptions that may alter the final color balance.

GIA’s 2025 study of the Winston Red revealed a strong 550 nm band with contributions from N3, H3, and H4 centers, as well as very pronounced deformation lamellae.

This confirms an important point: red is not necessarily a “new” atomic mechanism separate from pink. It may represent an exceptionally specific result of the concentration, distribution, and combination of defects within a connected system.

Fancy Red Is a Special Grading Category

In the GIA system, the official hue description of a dominantly red diamond must end with the word red.

Fancy red is used for pure dominant red. Because red occupies a very narrow range of tone and saturation, GIA does not apply the full sequence of Fancy Light, Fancy Intense, or Fancy Vivid to dominant red.

This means that Fancy red is not “one step above Fancy Vivid Pink.” It is a separate category of dominant hue.

Factual snapshot—GIA research, 2025.
In a database of more than one million natural fancy-color diamonds analyzed by GIA, predominant red accounted for approximately 0.07% of that population, while unmodified Fancy red accounted for about 0.04% of all fancy-color diamonds in the set. These are laboratory population data, not statistics on total world production.

[VISUAL 35.3: Fancy Deep/Vivid Pink toward the Fancy red area—hue, tone, and saturation as separate dimensions, without the linear logic that “red is higher pink”]

Purple Is Not the Same as Violet

In everyday usage, purple and violet are often treated as near-synonyms. In professional colored-diamond nomenclature, these two terms should not be equated.

Purple may be part of the pink–red deformation continuum, for example:

• purplish pink;
• pinkish purple;
• purple.

Violet more often belongs to a separate blue–gray–violet group with different causes of color, which is discussed in Chapter 36.

The final word of the full laboratory hue name must therefore be preserved exactly.

Modifiers Change the Character of Color

Pink may have a brownish, orangy, purplish, reddish, or grayish component. These hues are not semantic decoration; they can materially alter the perception and laboratory name.

For example:

• brownish pink is not the same as pink;
• orangy pink is not the same as pinkish orange;
• purplish pink is not the same as pinkish purple.

A modifier does not in itself say whether a stone is “better” or “worse.” That is a separate aesthetic and market question.

Zoning, Size, and Faceting

In pink and red diamonds, the spatial distribution of color can be decisive.

Face-up appearance is affected by:

• the density and distribution of colored lamellae;
• their orientation relative to the future table plane;
• the stone’s depth;
• shape;
• facet arrangement;
• reflections that multiply colored zones.

A recut can therefore change the color grade, but at the cost of weight, dimensions, historic geometry, or other properties. That decision is addressed in Chapter 24, not as an automatic recommendation in this chapter.

Argyle Is an Important Population, Not a Definition of Pink Color

Argyle in Western Australia was historically an exceptionally important source of strongly colored pink and red diamonds and developed its own trade nomenclature.

But three things must be kept separate:

1. a GIA or other laboratory color grade;
2. Argyle’s historic trade system;
3. evidence of geographic origin.

An Argyle-like appearance is not proof that a stone comes from Argyle. A trade designation is not a substitute for an independent laboratory grade.

[VISUAL 35.4: Laboratory Pink/Red grade, an Argyle trade designation, and geographic provenance as three separate layers]

Treated and Laboratory-Grown Pink/Red

Pink and red color can be produced or modified through combinations of:

• HPHT processing;
• irradiation;
• annealing;
• creation and redistribution of NV centers.

Laboratory-grown CVD and HPHT diamonds can also have highly convincing pink to red colors.

The natural origin of color therefore cannot be assessed from hue, intensity, fluorescence, or a single spectral center alone.

Detailed treatment and origin-of-color protocols follow in Chapters 39 and 60–63.

How to Read a Pink–Red Report

In a professional reading, check separately:

1. the full official hue name;
2. the dominant final word;
3. the intensity category;
4. color distribution;
5. color origin;
6. natural or laboratory-grown status of the material;
7. clarity and transparency;
8. shape and the way faceting concentrates color;
9. documented provenance, if Argyle or another geographic origin is claimed.

Fancy red may be extremely rare, but rarity alone does not replace examination of the stone’s other properties.

Chapter Summary

• The vast majority of natural pink and red diamonds, as well as some purple diamonds, are associated with the broad 550 nm absorption band and plastic deformation.
• The exact atomic structure of the most common 550 nm pink center has not yet been conclusively resolved.
• Pink graining and colored lamellae are not the same as a surface fracture or scratch.
• Natural deformation-related pink can occur in different diamond-type groups.
• Rare natural NV pink exists, but NV centers are common in treated and laboratory-grown material as well.
• The term “Golconda pink” must not be used as automatic proof of geographic origin.
• Natural Fancy red often belongs to the same deformation system as pink, with a specific concentration and combination of absorptions.
• In the GIA system, dominant red receives the Fancy red category, not a full sequence of intensity grades.
• GIA’s large research population confirms the extreme rarity of predominant red and unmodified Fancy red diamonds, but those percentages are not world production statistics.
• Purple and violet are not automatically synonymous in colored-diamond nomenclature.
• The modifiers brownish, orangy, purplish, reddish, and grayish change the full hue description but are not in themselves a market judgment.
• The orientation of lamellae, depth, shape, and faceting can strongly alter face-up pink/red appearance.
• Argyle is an important geologic and historic population, but its trade system is neither a universal grading standard nor proof of provenance.
• Treated and laboratory-grown diamonds can reproduce highly convincing pink and red colors; origin of color requires a body of laboratory evidence.