9
$\begingroup$

We know that Mars has a reddish color, because its ground consists of iron-based compounds. The moon is grey-whiteish because it consists mostly of silicon-based compounds.

What element should the moon in my world have in order to have a blue color?

I thought about cobalt-based compounds, but naturally this element is silver-grey.

$\endgroup$
  • $\begingroup$ Does your moon have an atmosphere? $\endgroup$ – L.Dutch - Reinstate Monica Feb 24 '19 at 8:04
  • $\begingroup$ @L.Dutch I prefer moon without any atmosphere. $\endgroup$ – Mr.D Feb 24 '19 at 8:07
9
$\begingroup$

You don't need an element, you need a mineral.

Certain elements do tend to make things a certain colour, for example nickel will make minerals green, manganese pink, and cobalt purple.

The fact that cobalt itself is a metal is irrelevant. Whatever "element" you have will not be metallic, it will be as a cation (or anion) in the silicates.

So your question should be rephrased to:

What element do I need to make the silicates the moon is made of, blue?

You have several options.

  1. Add sodium and chlorine, in order to make sodalite: Na8Al6Si6O24Cl2 (with the other elements already abundantly present on the moon).

enter image description here

  1. Sodium and water, at high pressure and then somehow expose those rocks on the surface. You will have glaucophane: Na2(Mg3Al2)Si8O22(OH)2. This is the main ingredient of the terrestrial rocks known as blueschists:

enter image description here

  1. Tons more aluminium, so then you can stabilise corundum (Al2O3). When combined with the already abundant iron and titanium as trace elements, you end up with blue corundum. Also known as sapphire when in gem quality:

enter image description here

This should get you started. Other things you might consider are potassium and whatever makes amazonite (potassium feldspar) green-blue. Copper is also a good one, but the blue requires water that isn't common on the Moon.

| improve this answer | |
$\endgroup$
  • $\begingroup$ Thank you for your answer. $\endgroup$ – Mr.D Feb 24 '19 at 9:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.