I'm currently developing a sci-fi concept for animation which partially involves a typical "the earth has been overrun by XYZ" scenario.

One of the ideas for XYZ we're thinking of is a species of intelligent crystalline beings made of diamond -- or at least a diamond like material. These are large, arachnoid in shape and fast. They kill by piercing their pray with sharp, lance-like protrusions on the ends of their forelegs.

The problem is, thus far we've been thinking that the trick to killing these things has been 'shattering' what essentially equates to a CPU or central core suspended like the 'body' of your typical daddy long legs. Which makes sense if the material were diamond -- however we realised it might be more interesting if kinetic force like cannonballs and explosive shockwaves were less effective, and that the key was 'cutting them.'

Maybe we're bad writers, and we just can't drop the idea of our protagonist being forced to use a 'chain-blade' up close to combat one of these things, but visually we're very keen on just such a scenario. So if those among you more educated than us (i.e. all of you) could point us towards a material where 'cutting' or 'sawing' with what could be called 'super-chainsaws' is more feasible than explosives, large projectiles, or other methods of blunt force, it would be greatly appreciated.

We Do understand just such a material will probably not exist in crystalline form, thus losing the overall aesthetic we're aiming for -- but nonetheless we'd love to hear what you guys have to say in general regarding the question and context.

Thank you very much for your time.

  • $\begingroup$ Maybe rubber or ballistic gel? Though I think that it would still be destroyed by an explosion. $\endgroup$ – CoffeeIsLife Nov 10 '19 at 2:10
  • $\begingroup$ Maybe go with an exoskeleton made of chitin (just like terrestrial insects). $\endgroup$ – Karsten Theis Nov 11 '19 at 16:59

The crystalline property that would allow to cut the "diamond creature" (or whatever those things are in your universe) you are looking at is cleavage (a writer might also use a term in a wordplay). In crystallography, cleavage is the ability of crystals to crack or split in certain crystallographic directions. This mechanical property of crystalline media is associated with their internal structure (the ratio of adhesion forces in the crystal lattice) and does not depend on the external shape of the crystals. This property is also often utilized in the beginning of the process of fashioning the gemstones.

There is a fascinating demonstration with explanation: Crystals - Alan Holden 1958 (YouTube).

With diamonds you can do that too, just not always as easily as with mica: Diamond Cleavage (YouTube). Diamond (as well as fluorite, galena, topaz and some other minerals) possesses a so-called "perfect" cleavage, and the cleavage planes in diamond are parallel to the octahedral crystal faces [1, p. 30]:

Diamond cleavage

Figure 4.1 Two examples of directional-dependant properties in diamond. The cleavage planes are parallel to the octahedral faces, which are also planes of near maximum hardness. The easiest direction for sawing is at right-angles to the dodecahedral plane, which is also the plane of minimum hardness.


  1. Read, P. G. Gemmology, 3rd ed.; Elsevier Butterworth Heinemann: Amsterdam; Boston, 2005. ISBN 978-0-7506-6449-3.
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  • $\begingroup$ Based on further google searches into diamond cleaving and sawing, I just want to further ask if anything screams out to you as especially ludicrous (apart from the entire concept of course) if our protagonists wore visual aids that allowed them to view a 3D 'wire-frame' of the diamond organisms (akin to something like the Advisor or Sarine programs used by craftsmen today) in order to identify in real-time the directional weaknesses of the beasts -- and thus the best 'way' to swing their weapons at them. $\endgroup$ – Delirium Nov 11 '19 at 5:37
  • $\begingroup$ @Delirium I guess the protagonist should be up-close and either have an optical device measuring light interference, or have an x-ray source and a properly placed detector. The latter would indeed reveal the structure and not just cleavage directions, but such an apparatus is at least of a size of a small fridge and requires cooling and powering units. However, if the creatures grow naturally, made on a conveyor or share a hive-mind:), these directions will be the same among all of them. $\endgroup$ – andselisk Nov 11 '19 at 6:11

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