What is the cause of colours of nail

What is the cause of colours of nail

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Why the nails are of white colour from bottom? then why they are pink and again white in the end?

The Nightman is giving you a headstart to understand and read about nail colour.

I would like to add a different view to this question from "Colour and Pathology" point of view. Finger nails have been an excellent source of evidence for the initial physical diagnosis process. Nail colour and texture can be an indiator for a wide range of medical conditions.

You may take a look at this link : The hand in Diagnosis Process and discusses about nail pathology.. However this diagnosis gets a little tedious if the patient has colourfully painted their nails with nail polish…

I see many of the answers do include an image - well at the end it's anatomy.

Here's a relative simple and fun to read article to clarify any doubts you have about Keratin in nails being dead or not, for its colour and why it's tough.

The cuticle and matrix are white because the melanocytes there are inactive, so there is no pigment produced. The matrix cells divide and the new cells produce a lot of keratin protein.

The older cells fill with keratin and die, and the new cells push them out of the way - this means toward the end of your finger. This is how your nails grow.

But our fingernail doesn't look like individual cells. You are sloughing millions of skin cells each day, but for a nail the dead cells all mass together. Nails only wear away or must be trimmed. Individual cells are not lost. The solidity of the nail comes from the connecting of the dead cells together by junctions between the cells called desmosomes, and by the interlocking of the cells like jigsaw puzzle pieces. But there's more.

Individual keratin protein filaments also become connected so that the entire mass of keratin becomes one solid structure. This is called cornification, like the stratum corneum (the outer, dead layers) of your skin.

One of the two main forms of keratin in your nails is crystalline keratin, which is rigid, stronger, and has an ordered structure - like a tinker toy cube. Transmitted light is less likely to strike an atom and bounce back when the atoms are all lined up, so this is why many crystalline lattices appear translucent.

The Nail itself consists of dead keratinous cells that shrink upon dying and become translucent. This gives the nail itself its white coloration. The reason it appears pink when it overlaps the finger is because of underlying blood vessels that color the live tissue pink just like your skin, and this shows through the nail itself. The lunula is the most proximal region of the fingernail that is crescent shaped and appears more white than the rest of the nail bed. The reason for the whiter color is that the underlying blood vessels are obscured by a denser stratum basale (one of the lower layers of the skin).

See: Human Anatomy by Martini If you don't have this book, you could at least start at wikipedia which does describe the anatomy of the fingernail with more or less accuracy: Wikipedia


Leukonychia describes a whitish discoloration of the nail, which may be due to persistence of nuclei in the cells of the ventral nail plate (true leukonychia), or to a pallor of the nail bed (apparent leukonychia). True leukonychia does not fade with pressure and moves distally with nail growth it is most commonly caused by trauma. Apparent leukonychia, which does not follow nail growth and fades with pressure, may be a sign of systemic diseases such as liver cirrhosis (Terry's nails Chapter 148 ), chronic renal diseases (half-and-half nails, characterized by apparent leukonychia of the proximal half of the nail Chapter 132 ), hypoalbuminemia ( Chapter 123 ), and systemic chemotherapy (Muehrcke's lines Fig. 450-8 ).

Black Toenail: Common Causes

If your toenail turns black, it’s most likely a bruise under the nail, technically called a subungual hematoma. You can get it from stubbing a toe or from footwear that cram your feet into the front of the shoe. The bruise usually starts out red, then becomes purple, dark brown, and finally black when blood beneath the nail pools and clots. Expect your black toenail to grow out in about 6 to 9 months or longer.

How Color-Changing Nail Polish And Atmospheric Sciences Are Related

There are all types of things that present opportunities to teach about science. This afternoon my wife's trip to the nail salon is one of them. In a social media post at the nail salon she said, "Color changing! This should be fun if it actually works." I was immediately curious because I was not familiar with this at all, and my wife is pretty diligent about her nail care. After a little research, I discovered that color-changing nail polishes exist. My hunch was that the science of how this happens might involve my area of expertise, atmospheric science. I was right.

Color-changing nail polish

The basic premise is that the nail polish looks one color inside but changes color when exposed to sunlight or heat. How does that work? In order to explain, I have to introduce something called the electromagnetic spectrum. As a former NASA scientist, I knew that the space agency would be a good place to find a definition: According to a NASA website,

Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. The human eye can only detect only a small portion of this spectrum called visible light. A radio detects a different portion of the spectrum, and an x-ray machine uses yet another portion. NASA's scientific instruments use the full range of the electromagnetic spectrum to study the Earth, the solar system, and the universe beyond.

As you can see in the graphic below, the electromagnetic spectrum is a part of many aspects of our lives. The Sun is the star that powers our solar system and its energy is important for life on Earth. Because of the Sun's temperature, the peak intensity of electromagnetic energy from the Sun is in the form of visible energy. Our eyes can see a narrow portion of those wavelengths. The Sun also emits a good portion of its energy at Infrared (IR) wavelengths. We cannot see this type of energy, but we can sure feel it as heat on our skin. The Sun even emits energy at sound wavelengths special solar radio telescopes can actually detect that energy.

There is another type of energy emitted by the Sun that can be harmful in large doses. It is called Ultraviolet (UV) radiation. At excessive amounts, UV radiation can be harmful to our skin or eyes. Thankfully, the stratosphere (the layer just above the troposphere in which we live) has a layer of ozone. Ozone is a gas that has three atoms of oxygen in its molecule rather than two atoms like the oxygen we breathe. When scientists discovered the ozone "hole" being caused by products containing various types of chemicals (such as CFCs), there was immediate concern because it is a natural filter of the Sun's harmful UV radiation. Over time, the Montreal Protocol was advanced and many of the ozone-depleting chemicals were banned from spray cans, refrigerants and so forth.

Ok, let's get back to the color-changing nail polish. According to,

Thermal polish changes color because it contains a leuco dye. The word “leuco” is a Greek word that means “white.” This is because a leuco dye has two forms: one is clear or colorless (white or leuco), while the other is colored. The reversible transition between the two colors may be caused by heat (thermochromism), light (photochromism) or pH (halochromism). It’s also possible to irreversibly change colors, usually from a redox reaction.

This suggests that as the nail is exposed to different heat (IR) environments, the polish would change. This means that changes in body temperature or exposure to a different temperature environment (warm water after hand-washing or the sun reappearing from behind a deck of clouds) might cause a transition. also describes a products that are sensitive to changes in UV radiation. The site says,

When exposed to ultraviolet light from the sun (or other long-wave UV source), UV nail polish changes color! The change is reversible. When the UV Nail Polish is removed from sunlight, it returns to its original color! Although the product is great for nails, it can just as easily be painted on an index card or acetate to make an ultraviolet light detector that can be used for testing the effectiveness of sunscreen lotion or any other UV filter.

When my wife gets home, I hope she accepts becoming data for the atmospheric scientist in the house. The hubby will catch up later.

If your fingernails are green&hellip

Nails have you looking like a swamp creature? Chances are you&rsquove got a bacterial nail infection. Bacteria called Pseudomonas aeruginosa cause blue-green discoloration of the nail plate, commonly in people whose hands are often in freshwater, says Feely. These bacteria thrive in warm, wet environments which means they&rsquore found all over the great outdoors and potentially in the jacuzzi, too.

Typically, this nail infection isn&rsquot painful &mdash just a bit swollen and unsightly. The fix? A visit to the doctor for oral or topical antibiotics, Lipner says.

What Should You Do?

Don’t ignore changes in your nails, but don’t jump to conclusions either. Nails that aren’t smooth or aren’t one color can be a sign of many diseases -- or of none. Only your doctor can tell for sure.

Look for the usual suspects before you assume a serious problem. Bruises, under-the-nail bleeding, and fungal infections are the main cause for nails to crack, peel, or change color and texture. Though common, fungal infections can be hard to treat. If your symptoms don’t go away, see a dermatologist.

Nail changes are rarely the first sign of illness. Other symptoms almost always appear before that happens. For instance, emphysema causes breathing problems much earlier than it does clubbed nails.

An illness may cause nail changes in some people but not in others. Not everyone with liver disease will develop white nails, for example -- and not everyone with white nails has liver disease.


Joshua Fox, MD, director, Advanced Dermatology spokesman, American Academy of Dermatology, West Islip, NY.

Sometimes, diseases that involve other organs (systemic diseases) can cause changes in the nails as well, including the following:

Iron deficiency may cause spoon-shaped nails (koilonychia). This deformity is particularly characteristic of Plummer-Vinson syndrome.

Kidney failure may cause the bottom half of the nails to turn white and the top half of the nails to turn pink or appear pigmented (half-and-half nails or Lindsay nails). This dystrophy can also occur in healthy people.

Cirrhosis may cause the nails to turn white, although the very top part of the nails may remain pinker. Intensely white nails, also called Terry nails, can be present not only in people with cirrhosis but also in those with chronic heart failure or diabetes. Terry nails may sometimes occur as part of normal aging. Low blood levels of the protein albumin (which may occur in people with cirrhosis) can cause horizontal white lines to form on the nails.

Some lung diseases, often accompanied by lymphedema (an accumulation of lymphatic fluid in tissues), may cause yellow nail syndrome, in which nails become thick, overcurved, and yellow or yellow-green in color.

Beau lines are horizontal grooves in the nail that occur when there is temporary slowing of growth of the nail. Sometimes the grooves can go all the way through the nail, leading to complete loss of the nail. They can occur after an infection, injury, systemic illness, or chemotherapy.

White horizontal lines across part of the nail (leukonychia) may appear after an injury. However, lines that run horizontally all of the way across the nail (Mees lines) may be associated with more serious health problems, including cancer or heart failure, chemotherapy, or exposure to certain toxins, such as arsenic, thallium, or other heavy metals. The nails can grow out normally if exposure to these toxins or chemotherapy is stopped.

Your nails are yellow.

Stern notes that most commonly, nails turn yellow because of nail polish use. But if you haven't been chronically polishing, it could be something called yellow nail syndrome. "With yellow nail syndrome, nails appear thick and have a yellow/green hue," Stern explains. "They frequently lack a cuticle as well as a lunula (the half moon at the base of the nail that is usually visible on the thumb and great toe)." This syndrome is a sign that the nails weren't able to grow correctly, and is often due to a lung condition called bronchiectasis or lymphatic disease. "Bronchiectasis is a condition in which damage to the airways causes them to widen and become flabby and scarred," Stern explains. It's usually the result of an infection or another condition like lung cancer, and can compromise circulation, which effects nail growth. "Because bronchiectasis tends to be chronic, yellow nail syndrome does, too." Problems with the lymphatic system can impact circulation, preventing "oxygen, nutrients, and blood from getting to extremities," Stern explains, and sometimes causing yellow nail syndrome.

What is a peacock feather up close?

Each feather consists of thousands of flat branches (as shown above in the detail). When light shines on the feather, we see thousands of glimmering colored spots, each caused by minuscule bowl-shaped indentations. Stronger magnification reveals microscopic lamellae (thin plate-like layers) at the bottom of the indentations. As with butterfly wings, the regular pattern of the lamellae leads to interference phenomena and iridescent colors. The feathers of pheasants, birds of paradise, and hummingbirds create color using the same mechanism.

View at different angles.
The changing colors of a peacock feather are due to the change in angle of incident light, combined with a complex structure of indentations and plate-like layers called micro-lamellae.

Underside of the feather.
Each branch has round indentations, with micro-lamellae on the bottom of each indentation that disperse the incident light, coloring the feathers.

The white color of this unusual peacock is due to lack of dark pigment. The usual rich colors of the peacock are seen because black pigment absorbs most of the incident light, allowing us to see only the interference colors. In this peacock, the interference is present, but the effect is entirely washed out by the abundance of white light. Here you can see that the "eyes" of the tail feathers are transparent, not colored.

Major plant pigments and their occurrence

PigmentCommon typesWhere they are foundExamples of typical colors
ChlorophyllsChlorophyllGreen plantsGreen
CarotenoidsCarotenes and xanthophylls (e.g. astaxanthin)Bacteria. Green plants (masked by chlorophyll), vegetables like carrots, mangoes and so on. Some birds, fish and crustaceans absorb them through their dietsOranges, reds, yellows, pinks
FlavonoidsAnthocyanins, aurones, chalcones, flavonols and proanthocyanidinsProduce many colors in flowers. Common in plants such as berries, eggplant, and citrus fruits. Present in certain teas, wine, and chocolateYellow, red, blue, purple
BetalainsBetacyanins and betaxanthinsFlowers and fungiRed to violet, also yellow to orange


Chlorophyll is green, and is responsible for the green color of foliage and leaves. More importantly, by enabling plants to produce oxygen during photosynthesis, it is critical to sustaining our life on earth. Chlorophyll has structural features similar to heme. Bilirubin, which produces a yellow color, has recently been found in plants.

Red, orange, and yellow plants, as well as other organisms, generally rely on carotenoids for their vivid colors.


Carotene is a pigment that absorbs blue and indigo light, and that provides rich yellows and oranges. The distinctive colors of mango, carrots, fall leaves, and yams are due to various forms of carotene, as is the yellow of butter and other animal fats. This pigment is important to our diet, as the human body breaks down each carotene molecule to produce two vitamin A molecules.

Lycopene, canthaxanthin, and astaxanthin share a similar structure to carotene. The red tones of tomatoes, guava, red grapefruit, papaya, rosehips, and watermelon indicate the presence of lycopene.

Canthaxanthin produces the pink colors of flamingos, some crustaceans, salmon, and trout. In its synthetic form, it is used to ensure captive flamingos retain their coloring, as a red food colorant, and even as a tanning aid. Astaxanthin provides the red colors of cooked salmon, red bream, trout, lobster, and shellfish. In a live animal, astaxanthin is combined with a protein and is blackish in color. When boiled, the protein breaks down to unmask the true &ldquolobster red&rdquo of astaxanthin.


Flavonoids are the yellow plant pigments seen most notably in lemons, oranges, and grapefruit. The name stems from the Latin word "flavus," which means yellow. Flavonoids in flowers and fruit provide visual cues for animal pollinators and seed dispersers to locate their targets. Flavonoids are located in the cytoplasm and plastids. Many of the foods that we eat, including dark chocolate, strawberries, blueberries, cinnamon, pecans, walnuts, grapes, and cabbage, contain flavonoids. These chemicals lower cholesterol levels, and many have antioxidant properties. Anthocyanins and proanthocyanidins, and the reddish-brown pigment theaflavin found in tea, act to create color, while most other flavonoids are visible only under UV light.

Flavonoids include red, purple, or blue anthocyanins, as well as white or pale yellow compounds such as rutin, quercetin, and kaempferol.

Anthocyanins play a role in the colors of ripening fruit. They are found in most other plant parts and in most genera. Anthocyanin pigments take their color from the range of red, purple, or blue, depending on their pH. Blueberries, cranberries, and bilberries are rich in anthocyanins, as are the berries of the Rubus genus (including black raspberry, red raspberry and blackberry), blackcurrants, cherries, eggplant peel, black rice, Concord and muscadine grapes, red cabbage, and violet petals. Anthocyanins are partly responsible for the red and purple colors of some olives.

Proanthocyanidins are linked to the beige color of the broad bean seed coat, and also to shades of black, red, brown, and tan. Apples, pine bark, cinnamon, grape seed, cocoa, grape skin, and the grapes used to make most red wines all contain proanthcyanidin.

The yellow colors of flavonoid pigments can be found as chalcones (found in flowers and the organs of plants), aurones (found in flowers and some bark, wood, or leaves) and flavonols.


Like carotenoids and flavonoids, betalains also seem to play an important role in attracting animals to flowers and fruit, and produce a similar range of colors. The betalains consist of two sub-groups, red-violet (betacyanin) and yellow to orange (betaxanthin) pigments. They only occur in a few plant families, and always independently of anthocyanins.

Betacyanins are established food colorants. Betalains give rise to the distinctive deep red of beetroot. The composition of different betalain pigments can vary, giving rise to breeds of beetroot that are yellow or other colors, in addition to the familiar deep red. The betalains in beets include betanin, isobetanin, probetanin, and neobetanin (the red to violet ones are known collectively as betacyanin). Other pigments contained in beet are indicaxanthin and vulgaxanthins (yellow to orange pigments known as betaxanthins). Betalains cause the crimson of Amaranthus flowers (class of Caryophylalles).

Interestingly, betalains are only found in one sub-group of flowering plants (Caryophylalles or Centrospermae). Bougainvillea, certain cacti, and amaranth are all examples of this family. These plants lost, or never acquired, genes for the synthesis of other plant pigments. Genes for the synthesis of betalains appear in unrelated fungi (such as Amanita muscaria) as violet and yellow pigments.

Betalains are close in structure and in their synthesis to the animal pigment group melanins, and to eulamelanins in particular.