I have a creature that is made of crystal. The problem is, crystal as I know it is structured in ways that don't allow for flexible movement as we are able to do. How could a lifeform made of crystal move like us? What about a rock creature?

It has a spherical body and 2 arms and 2 legs. Basically generic Kirby character or Smash Bros Pacman shaped.

  • $\begingroup$ It would seem to me that you'd have to rely on physics to move, rather than chemistry. Human muscles rely on a ladder ratchet system made of proteins to move, but the proteins are orders of magnitude more complex and ordered than most crystals. I'd advocate for some sort of magnetic effect, but I'd need to research more. $\endgroup$ Commented Jan 30, 2020 at 0:18
  • $\begingroup$ Tbh most fiction I've read or watched handwaves most of the physics of crystal movement. $\endgroup$ Commented Jan 30, 2020 at 0:19
  • $\begingroup$ Rock creature... do you mean coral? $\endgroup$
    – user6760
    Commented Jan 30, 2020 at 1:48
  • 1
    $\begingroup$ @user6760 No. Corals grow on rocks, but they themselves are not rocks. $\endgroup$ Commented Jan 30, 2020 at 1:58
  • $\begingroup$ A more detailed description of your creature might help get you answers. Is it bipedal? Is it spherical? $\endgroup$
    – kleer001
    Commented Jan 30, 2020 at 20:31

4 Answers 4


Some of it has to be not-crystal. Or at the very least another form of that crystal.

But that's okay, there's no living creature that's entirely homogeneous.

Chitin comes in several forms with different properties: https://ibiologia.com/chitin/

Keratin also comes in several forms: https://en.wikipedia.org/wiki/Keratin

You can do the same with your creature. Give it a hard structural type and a flexible type of crystal, a light sensitive type, etc...

You'll probably need a circulatory system to get stuff from one place to another too.

Barring that you could hand wave away your problem with magnets or ultrasonics.


Movement is work. Work is based on the expenditure of energy. The assumption is your crystal creature is "alive" because of some kind of crystal based energy that is consumed and replenished in some regular basis. Movement would then be based on expenditure of that accumulated energy. Is that energy expenditure expensive or is it efficient and easy? Quartz watches work because the crystal structure vibrates in a natural fashion. Your crystal creature could move by expending energy in such a way that it vibrated in such a way that it could move from place to place. Most likely your crystal creature does something like the Michael Jackson moonwalk.. smooth and seemingly effortless.


There's some organic crystalline structures that flex by sliding across each other like sheets of paper. If you can imagine something moving with that kind of motion, maybe with thousands of microscopic crystalline hairs sliding around like a snail.


  • $\begingroup$ How strong of a material would this be? Would this movement appear different than how we move? $\endgroup$ Commented Jan 30, 2020 at 1:26
  • $\begingroup$ If we're looking at this as a principal rather than a specific material (since several different substances seem capable of it) I would *guess that it would range from as squishy as normal organic creatures to something quite hard but also brittle. An impact might kind of 'splatter' it, causing the layers to lose cohesion temporarily like throwing a notepad on the ground. The actual movement would be at a molecular or microscopic scale so it would probably appear to be sliding and bending like a slug or something. $\endgroup$ Commented Dec 15, 2023 at 9:27

Migratory recrystallization.

Ice recrystallization is strongly inhibited when antifreeze proteins bind to multiple ice planes

As shown, the ice grains underwent recrystallization with time (t) in different manners including; (i) uniform growth with keeping a relatively round shape (indicated by arrows), (ii) shrinkage by melting and disappearing, or (iii) merging to become larger ice grains (accretive recrystallization). The (i) and (ii) are known as migratory recrystallization.

At the joints, the crystals of your creature fracture into smaller crystals. These smaller crystals might melt and disappear, their substance adsorbed to the surface of adjacent crystals. Or they might merge and form larger crystals. The moving interfaces of a crystal creature are constantly fragmenting and recrystallizing.

  • $\begingroup$ This sounds like it would make for a slow creature though $\endgroup$ Commented Feb 1, 2020 at 3:34
  • $\begingroup$ @ChickenpeepChickenpeep - crystals can form very fast. Youtube search "supercooled ice". $\endgroup$
    – Willk
    Commented Feb 1, 2020 at 14:28

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