Why don't you give a percentage for green eyes?

Because the percentages in circulation come from studies that categorised eye colour differently and sampled different populations. Presenting one of them as a global figure would give a false impression of precision. The honest claim — that green is widely described as the least common broad category — is recorded instead, with its confidence marked low.

Is blue really rare in nature?

Blue pigment is rare; blue appearance is not. Most blues in feathers, wings and shells are produced by microscopic structures scattering light rather than by a blue pigment. That is a claim about mechanism, not about how often blue-looking organisms occur.

What is the most popular colour?

Blue is the most frequently chosen favourite in surveys across many countries. That is a claim about stated preference in the abstract, which predicts remarkably little about what people actually choose for a car, a wall or a shirt.

What is the rarest colour?

Short answer

The question has no answer until it says rarest among what. The rarest eye colour, the rarest colour in nature and the rarest historical pigment are three unrelated questions, measured in different ways among different populations. Anyone giving a single confident answer has silently picked one of them.

Why scope changes the answer

Rarity is a ratio, and a ratio needs a denominator. “Blue is the rarest colour in nature” is about the mechanisms available to living things. “Green is the rarest eye colour” is about the distribution of a human trait. “Ultramarine was the rarest pigment” is about the cost and supply of a material at a particular time in a particular place. None of these can be ranked against the others, and combining them into one league table — which is what most articles on this question do — produces a result that means nothing.

There is a second problem. Even within one domain, published figures often come from studies that defined their categories differently. Two eye-colour surveys that draw the line between green and hazel in different places will disagree about how common green is, and neither is wrong. Every claim below therefore carries its population, its method and an explicit statement of what it does not establish. Where no reliable figure exists, this page says so instead of supplying one.

Eye colour

Brown eyes

high confidence

Brown is consistently reported as the most common eye colour worldwide, by a wide margin over every other broad category.

Where: Worldwide
Among whom: General human population, all ages
When: Contemporary (late 20th century onward)
What is measured: Prevalence in a population
Evidence: General genetics and clinical reference literature
How: Broad-category summary across multiple reference sources rather than one global survey; no single study samples the whole world population.

What this does not show: Establishes ordering, not a precise share. Published percentages vary widely with how 'brown' is bounded against light brown, hazel and amber, and with which populations were sampled.

Sources: MedlinePlus Genetics: Eye colour; Colourwise editorial synthesis

Green eyes

low confidence

Green is widely described as the least common of the broad eye-colour categories, but no reliable single global figure exists for it.

Where: Varies by source; strongest evidence from European and North American samples
Among whom: General population
When: Contemporary
What is measured: Prevalence in a population
Evidence: General genetics and clinical reference literature
How: Qualitative summary. Studies differ on whether green is a category of its own or is grouped with hazel, which changes the count substantially.

What this does not show: No percentage is given deliberately. The figures circulating online derive from studies with incompatible category definitions and unrepresentative samples; presenting one as a global rate would be false precision.

Sources: MedlinePlus Genetics: Eye colour; Colourwise editorial synthesis

Grey eyes

low confidence

Grey eyes are generally considered uncommon, but many studies do not record grey separately from blue, so dedicated prevalence data is limited.

Where: Varies by source
Among whom: General population
When: Contemporary
What is measured: Prevalence in a population
Evidence: General genetics and clinical reference literature
How: Qualitative summary; the category is frequently absent from the classification schemes used.

What this does not show: A claim about how often grey is *recorded*, which is not the same as how often it occurs. Absence from a study's categories is not evidence of rarity.

Sources: MedlinePlus Genetics: Eye colour; Colourwise editorial synthesis

The natural world

True blue pigment in living things

medium confidence

Genuine blue pigments are rare in living organisms. Most blues in nature — in feathers, butterfly wings and many berries' sheen — are produced by microscopic structure scattering light rather than by a blue pigment.

Where: Worldwide
Among whom: Plants and animals generally
When: Contemporary biology
What is measured: Frequency of occurrence
Evidence: General natural-science reference and botanical/zoological literature
How: Qualitative synthesis of the mechanisms described in reference literature, not a census of species.

What this does not show: A statement about mechanism prevalence, not a count. 'Rare' here means pigment-based blue is unusual relative to structural blue, not that blue appearances are unusual — blue-appearing organisms are widespread.

Sources: Royal Botanic Gardens, Kew; Natural History Museum, London; Colourwise editorial synthesis

Green in land plants

high confidence

Green is the dominant colour of land plant foliage, because chlorophyll absorbs strongly in the red and blue parts of the spectrum and reflects proportionally more green.

Where: Worldwide
Among whom: Land plants
When: Contemporary biology
What is measured: Frequency of occurrence
Evidence: Botanical reference literature
How: Mechanistic explanation supported by general botanical reference sources.

What this does not show: Describes typical foliage. It does not extend to flowers, fruit, fungi, marine algae or non-photosynthetic tissue, where the dominant colours differ entirely.

Sources: Royal Botanic Gardens, Kew; Encyclopaedia Britannica; Colourwise editorial synthesis

Pigments and dyes

Natural ultramarine (lapis lazuli)

medium confidence

Natural ultramarine, ground from lapis lazuli, was among the most expensive pigments available to European painters before a synthetic route was found in the 19th century — costly enough that its use was often specified in commissioning contracts.

Where: Europe
Among whom: Painters and workshops
When: Roughly 13th to early 19th century
What is measured: Qualitative description
Evidence: Museum and art-historical reference material
How: Historical/art-historical synthesis. Relative cost, not a single price — prices varied enormously by period, source and purity.

What this does not show: A claim about historical cost and scarcity of supply, not about the pigment today. Synthetic ultramarine is inexpensive and widely available, so this says nothing about modern rarity.

Sources: The National Gallery, London (conservation and pigment research); Encyclopaedia Britannica; Colourwise editorial synthesis

Tyrian purple

medium confidence

Tyrian purple was extraordinarily labour-intensive to produce, requiring very large numbers of murex sea snails for a small quantity of dye, which is the practical reason it became associated with wealth and rank.

Where: Mediterranean
Among whom: Dyers and textile production
When: Antiquity through the medieval period
What is measured: Qualitative description
Evidence: Museum and historical reference material
How: Historical synthesis from museum and encyclopaedic references.

What this does not show: Quantities cited in ancient and modern sources vary considerably and should be treated as illustrative of scale rather than as measurements.

Sources: The Metropolitan Museum of Art (Heilbrunn Timeline of Art History); Encyclopaedia Britannica; Colourwise editorial synthesis

Human preference

Blue as a stated favourite colour

medium confidence

Blue is the most frequently chosen favourite colour in survey after survey across many countries — one of the more consistent findings in colour preference research.

Where: Strongest evidence from Western Europe, North America and other industrialised countries; coverage elsewhere is thinner
Among whom: Adults responding to preference surveys
When: Mid 20th century onward
What is measured: Stated preference
Evidence: Published colour-preference survey literature
How: Self-reported preference from surveys. Results depend on how the question is asked, which options are offered, and whether a context is specified.

What this does not show: A stated preference in the abstract, which predicts very little about what people actually choose for a specific purpose — favourite colour and chosen car, wall or clothing colour diverge sharply.

Sources: Encyclopaedia Britannica; Colourwise editorial synthesis

Common questions

What is the rarest colour?: There is no answer to that question as asked, because it does not say rarest among what. Rarest eye colour, rarest colour in nature, rarest historical pigment and least popular colour are four different questions with four different answers, measured in different ways among different populations. This page answers each separately and states the scope of every claim.
Why don't you give a percentage for green eyes?: Because the percentages in circulation come from studies that categorised eye colour differently and sampled different populations. Presenting one of them as a global figure would give a false impression of precision. The honest claim — that green is widely described as the least common broad category — is recorded instead, with its confidence marked low.
Is blue really rare in nature?: Blue pigment is rare; blue appearance is not. Most blues in feathers, wings and shells are produced by microscopic structures scattering light rather than by a blue pigment. That is a claim about mechanism, not about how often blue-looking organisms occur.
What is the most popular colour?: Blue is the most frequently chosen favourite in surveys across many countries. That is a claim about stated preference in the abstract, which predicts remarkably little about what people actually choose for a car, a wall or a shirt.

Go further

Rare and common eye colours Rare colours in nature Common colours in nature Historical pigments How colour works How Colourwise handles evidence

Every claim on this page is required to state its geography, population, time period, dataset, method and limitations before it can be published; claims that cannot are not rendered. Confidence is recorded per claim, and a low-confidence claim is shown as such rather than being quietly dropped or quietly promoted.