I've decided that the reason my Orcs have green skin is because they have two pigments in their skin cells. The first is melanin, which works the same way as it does for Humans, with the amount of melanin affecting how light or dark their skin is. The second pigment needs to be something else, though I'm not sure what, exactly. There are two primary things I want this pigment to accomplish:

  1. It needs to produce colors other than green. The pigment needs to be able to produce not only green skin but skin of other colors not found in humans, such as red, blue, and purple, potentially more. The idea is that colors other than green are a result of certain genes being more dominant, which usually correlates with certain advantageous attributes, namely greater Arcane or Psionic abilities. So, a red-skinned Orc is likely to be a powerful mage, a blue-skinned Orc is likely to be a powerful Psion, and a purple-skinned Orc is likely to be a Psionic Mage. Thus, these rare skin colors are generally viewed as positive traits, not negative.
  2. I would like for the green pigment to give Orcish skin somewhat more durability. I'm not sure if skin pigment can do that, so if that isn't feasible, I can have their resilient skin be a result of something else, though I like the idea of the green pigment having an additional function, the same way that melanin helps to protect us from certain types of UV light. I figured in keeping with the "Orcs are durable" idea I'm using, the green pigment could primarily be for making their skin tougher and less likely to scar when it is damaged. This would be why Orcs actually prize their scars so much; if they have one, it means the injury that caused it was not small but they survived it.

I'm wondering if there is something that could accomplish both these things. I was considering having the pigment be copper based. This is because copper is pinkish-orange on its own (which could result in red-skinned Orcs) but is also present in malachite (which is green) and azurite (which is blue.) That just leaves purple, but I haven't been able to find out if copper produces a purple color when combined with something else. However, as it can get three of the four colors I'm primarily after (green, red, nd blue,) it seems the best option for the pigment that gives a majority of Orcs green skin.

Am I on the right track or is there some other compound I should consider for these purposes?

  • $\begingroup$ related worldbuilding.stackexchange.com/q/93392/30492 $\endgroup$
    – L.Dutch
    Commented May 26, 2021 at 2:42
  • $\begingroup$ Related "How would a humanoid naturally grow green hair?" $\endgroup$
    – JBH
    Commented May 26, 2021 at 5:46
  • $\begingroup$ Astaxanthin. $\endgroup$
    – AlexP
    Commented May 26, 2021 at 12:00
  • 1
    $\begingroup$ Just as an aside, skin toughness is usually just a matter of thickness: e.g., a rhino hide is two inches (50 mm) thick in some places, as opposed to human skin which is a mere .079 inches (2 mm). $\endgroup$ Commented May 26, 2021 at 17:53
  • $\begingroup$ if you want orcs to have tougher skin just have them bath less frequently, human skin is noticeably tougher in societies where bathing is not a frequent occurrence. $\endgroup$
    – John
    Commented May 27, 2021 at 4:22

3 Answers 3


I think the copper minerals might work for the colours you've described, but you may need to tweak biology as copper tends to be poisonous. A copper mineral that is purple is Bornite.

An alternative chemical pigmentation is class of compounds, that do exist in nature as brightly coloured compounds, are porphyrins, there are the behind the colour of our blood and the colour of plants. They can take a variety of colours, depending on what is attached to the ring and on what metal is in the centre of the ring. For red, the heme group in blood is a porphyrin with an iron core and additions to the ring, and if it is a basic porphyrin with iron in the centre it is green enter image description here

if instead of iron, it is a copper atom, then the compound is blueenter image description here

and if its zinc, then you get purple

enter image description here

they are called iron, copper and zinc Phthalocyanine

An alternative to chemical colouration is Structural coloration would also work and it would be able to provide any colour you need, it is the method of coloration of peacocks feathers

enter image description here

and macaws

enter image description here

and many more creatures, almost no vertebrates have a blue pigment in them it is all from Structural coloration.

The color comes from microstructure in the skin that cause light to interact with itself, so that only the color you want is reflected.

Additionally the microstructure if they are made from harder materials (like calcium carbonate with Nacre) then it may add an additional toughness to your orcs skin.

hopefully that helps

  • $\begingroup$ I'm actually using structural coloration to account for how races like Elves, Gnomes, & Faeries have oddly colored hair, so while that is a viable explanation, it would also be a bit redundant for my story setting. If copper would be too toxic, I suppose I could go a different route & have the pigment be something non-toxic that is simply transmuted by an innate magic process so it reflects green light instead of absorbing it. It wouldn't be structural coloration, per se, as the structure isn't what's doing it, but it would control which wavelengths of light bounce off the pigment. $\endgroup$
    – user53529
    Commented May 26, 2021 at 3:34
  • 2
    $\begingroup$ @Patrick-Leigh copper isn't necessarily toxic, horseshoe crabs have copper in their blood. you just have to tweak your biology to work with it, not sure exactly how. I'll see about adding a bit about green/blue/purple pigments, ie not structural colouration. $\endgroup$
    – Nyra
    Commented May 26, 2021 at 8:27
  • $\begingroup$ I think porphyrins will definitely work. I also like that a different metal at the center produces a different color. That appeals to me quite a bit. I think I'll go with this and say that Orcs have porphyrins in addition to melanin in their skin. $\endgroup$
    – user53529
    Commented May 26, 2021 at 19:54

There are a number of small lizard species with green blood. Their hemoglobin is about the same color as ours, and there's no significant amount of copper in their blood (unlike the blue-green blood of horseshoe crabs): instead, their blood is colored by a biliverdin -- green bile.

When the liver breaks down red blood cells, the hemoglobin is split into two compounds, bilirubin (which produces red bile) and biliverdin (green bile); the former is an important aid in the digestion of fats, while the latter has little function in humans. In these families of skinks, however, the biliverdin is released into the blood plasma and colors the blood green, overriding the red that would normally come from the erythrocytes.

The evolutionary reason for this is uncertain, especially since some of the green-blooded skinks can interbreed with skink species that have red blood and produce viable, fertile offspring.

However: green blood alone would account for a greenish skin hue (just as red blood makes humans with low skin pigment pinkish). How the orcs get tougher skin is probably unrelated.


Use tattoos.

You want more than green - you want a lot of colors and you want them to have societocultural significance. It is easier for the orcs to choose that themselves. When they come of age (or occasionally later or even earlier - good for the story!) they get tats in the colors you want that signify who they are, where they belong and what they can do.

Just being colored a way because that is how you were born offers limited grist of the story mill. Choosing a color, or being colored offers more. If you become ashamed of your tattoo, what do you do?


You must log in to answer this question.