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Starting at the most basic of theoretical questions, is it chemically possible for these minerals to be deposited by an organic enzyme? I'm particularly interested in diamond because it's pure carbon, which is very plentiful in the environment. Perhaps, for example, one enzyme might set down methane molecules together to form a sort of seed crystal, then another enzyme might continue the process by stripping of a hydrogen atom and depositing methyl group in its place until the crystal grows to the right size. In short, is the energy required to form these diamond bonds too high for an organic enzyme to make?

Then, assuming that's possible, would a skeleton that uses diamonds have any significant advantage in terms of strength over the normal hydroxylapatite bones (assume the crystals are roughly the same size). Lastly, if diamond is a particularly poor choice for this application for whatever reason, would other gem grade minerals (e.g. quartz, corundum, beryl, etc.) function better?

In terms of the rest of this particular creature's anatomy, it's basically a human that's been augmented by magic. The magic has made all of its body systems as efficient as possible, in effect replacing the "good enough to breed" standard of evolution with "as close to perfect as humanly possible". However, I want to avoid using magic to make its body function on a day-to-day basis.

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    $\begingroup$ Hi. It is customary here to wait 24 hours before accepting an answer. That way people from all timezones have opportunity to came up with their own answers and explanations without feeling their work is no longer needed and will not be appreciated. It is, of course, just a custom, not a rule, writing this just so you know. $\endgroup$ – Mołot Apr 13 '18 at 9:00
  • $\begingroup$ Oh, that’s good to know. I’ll keep that in mind in the future. $\endgroup$ – Horik Apr 13 '18 at 17:01
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There is a fundamental reason why bones are not made by crystals.

Everyone seems to think that diamond is the strongest material, but have you ever wonder how does it come into the shapes you see decorating the fingers or the cleavages of those fine upper class, cocktail sipping, ladies?

Diamonds to not come out of the earth already fitting a ring, they need to be worked to the proper shape. And how do you cut the hardest known material?

Are NASA, FBI, Monsanto and the free masons hiding from us the "stronger than the strongest" material? No, crystals are very weak when a force is exerted in very specific direction, and they easily get cleaved.

When I started cleaving silicon wafers at the university, I was amazed that I could split a pizza size wafer in two just by a swift touch on the edge, while to split a pizza in two I had to use much more effort.

Now, when you are using your bones you don't want to worry that the forces you are applying to them are not oriented along those cleaving directions. That's why isotropic materials are preferred by Darwinian selection.

Also consider that when you put together two crystals with different orientations the boundary is a weak point. That's why putting together several micro-crystals would not be better than a crystal or than an amorphous and isotropic material like apatite.

P.S. Don't forward this answer to the final boss of any game where you wear diamond armor.

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  • $\begingroup$ I think you misunderstood my question a bit. I meant that the second enzyme would strip hyrdogen atoms away and replace them with a methyl group; in essence, leaving a core of diamond bonded to a sort of "shell" of methyl groups. I'll edit the question to make it a bit clearer what I meant. As for the weaknesses, couldn't that be solved by orienting some in one direction and others perpendicular to those? $\endgroup$ – Horik Apr 13 '18 at 5:24
  • $\begingroup$ @Horik, if you do that you will strongly decrease the resistance in the directions where the crystal is strong. $\endgroup$ – L.Dutch Apr 13 '18 at 5:33
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    $\begingroup$ So then what is it about apatite that makes it work in bones and enamel where "gemstones" wouldn't? $\endgroup$ – Horik Apr 13 '18 at 5:38
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    $\begingroup$ @Horik biology.SE would know!!! $\endgroup$ – RonJohn Apr 13 '18 at 5:45
  • $\begingroup$ @Horik, edited my answer to hopefully cover also that point. $\endgroup$ – L.Dutch Apr 13 '18 at 5:55
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Bones are so good because they are strong but also a little bit elastic. Gems don't have this.

For example see the The Brittle Bone Experiment (referenced below): in this experiment they remove all the organic material in a bone. What's left is only hard minerals. Should be really strong right? No, it would break the moment you fall from a high place. Why doesn't it break? Since it can bend a little bit.

detailed explanation

easy one

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  • $\begingroup$ you are visiting the site for a while already. You should know (if not, then it's time to learn it) that we like expanded answers. One liners like this are better used (and seen) as comments. $\endgroup$ – L.Dutch Apr 13 '18 at 7:14
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    $\begingroup$ I'm new, need to learn lots of things yet. $\endgroup$ – Moonhorse96 Apr 13 '18 at 7:21
  • $\begingroup$ that's the spirit. Don't be shy and flesh your answer a bit more ;) $\endgroup$ – L.Dutch Apr 13 '18 at 7:30
  • $\begingroup$ A reference to the experiment would be the cherry on the cake ;) $\endgroup$ – L.Dutch Apr 13 '18 at 8:13
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Bone is a composite, and has about 4-5 times stronger than steel by weight, switching to any regular crystal will just make it brittle.

diamond and quartz are hard not strong, (quartz is basically glass) you could snap a rod the thickness of your finger bones between your fingers. Bone is non-crystalline which is important, crystals are weak. There are actual diseases that cause bones to form crystalline structure and they make them very brittle in the process.

Could you make bones from something stronger, yes bone is rather poor as far as material strength, but the strength to weight ratio would end up being vastly inferior because your body still needs the calcium and phosphate so most of the bone weight will still be there. weight is a big issue, as it drastically effects the forces and calories needed to move.

Flexibility And elasticity is also an issue bone has really low Young's modulus so under excessive loads bend instead of breaks. there are very few material that can match both strength and Young's modulus of bone at the same time, including man made composites. Poor Wolverines joints are getting pounded into mush with every step, if he did not have a healing factor he'd be crippled within weeks because he has no shock absorption.

All of this could be overcome, but there is one final nail in coffin. Calcium and phosphate are water soluble and thus fairly easy to move around, so bone can be repaired constantly, and it has to be. The stresses we put on bone would result in constant micro-fractures no matter what you made it out of. Quartz especially would be very difficult to repair as silica has very low solubility.

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  • $\begingroup$ I'm not actually asking what would happen if the entire bone were made out of quartz/diamond/whatever. I'm asking what the bone would be like if the existing microscopic hydroxylapatite crystals in the bone were replaced with one of these other materials, maintaining a similar crystal size. Also, carbon is way more plentiful in the body than Ca and P are, so I would imagine making them out of diamonds wouldn't be overly difficult from a logistics standpoint. $\endgroup$ – Horik Apr 14 '18 at 2:52
  • $\begingroup$ pure carbon is not really soluble, and with the solubility issue you have problems forming linkages with the rest of the composite.could you do it yes but it will be weaker than bone and not be able to heal fast enough, so it will eventually break down. $\endgroup$ – John Apr 14 '18 at 3:49
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Possible yes, but a good idea probably not.

Bones are calcium, this is a mineral, it's a metal actually.

If organic biology can lay down one mineral then there's no reason to suppose evolution couldn't develop organisms that lay down other minerals.

Aside from the utility & usefulness of those other minerals to an organism as dictated by mother nature through evolution & natural selection of course.

There are in fact examples of other minerals laid down by organisms in the real world, some snails that live around deep sea vents do actually grow their shells out of another metal.

The only real question is would this other mineral provide an evolutionary edge to the organism that uses it for it's bones, most crystal probably isn't a good choice, at least not for bones, your diamond bones may be hard but will also be brittle, so lateral blows to long bones are pretty likely to cause it to shatter far more easily than our calcium bones, possibly not a good idea then.

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I would suggest some more exotic materials to strengthen bones.

Carbon nanotubes run through a ceramic substrate might be stronger than calcium. And the nanotubes have interesting electrical properties that could be used in the replacement for nerves also.

Diamond is hard, but also fragile. But I agree with using carbon, it has so many useful forms.

In addition to replacing the material the bones are made out of, I'd also think of the optimum shape for the nerves. The obvious shape is not always the best shape. For example, our spinal vertebrae are prone to being damaged by bending. Perhaps a differently designed spine would be better. The same with the long-bones.

Think of a solid square beam of steel. You can make this stronger and lighter by using an I-Beam of the same dimensions. They make more complex beams now that have more strength in more dimensions than the i-beam, but use more material and weigh more than the simple i-beam.

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  • $\begingroup$ The carbon nanotube idea is an interesting one, to be sure. I was actually entertaining the idea that there might be a sort of carbon fiber matrix to which the diamonds (or other crystals) would be embedded, which might then compensate for the weaknesses of the diamonds. As for the ceramics, is there a way to even deposit them without intense heat? $\endgroup$ – Horik Apr 15 '18 at 2:59

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