I have been browsing the internet, and I have started to wonder whether a diamond sword is feasible or not. I would very much like to know the answer.

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    $\begingroup$ Feasible in what sense? Could an advanced culture artificially create a diamond shaped like a sword? Could a diamond large enough to be carved into a sword develop naturally? Could a sword made out of diamond be used in combat? $\endgroup$
    – Brythan
    May 10, 2019 at 15:13
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    $\begingroup$ Welcome to Worldbuilding.SE Jacob. Glad you found us. Please check out our tour and help center to get a feel for the place. You're getting downvotes on your question (not from me) because you didn't give enough information. If you could please edit your question to account for the questions people asked in the comments, that would help. $\endgroup$
    – Cyn
    May 10, 2019 at 15:48
  • $\begingroup$ Sister site question Could a knife blade & shaft be made of 100% diamond? $\endgroup$ May 10, 2019 at 15:49
  • $\begingroup$ I realize you haven't yet earned the reputation needed to give upvotes but we do ask that questioners wait a full day or two before accepting an answer. This encourages others to answer and you might even find an answer you like better. There's no time limit on accepting and you'll still get your 2 points. $\endgroup$
    – Cyn
    May 10, 2019 at 15:50
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    $\begingroup$ A purist might argue that the linked duplicate isn't answering the question of feasibility directly. I counter: it's irrelevant. But, if you feel that isn't the best duplicate assignment, consider this, this, and this. Searching the site before asking a question is always a good thing. $\endgroup$
    – JBH
    May 10, 2019 at 23:41

5 Answers 5


You could, but it probably wouldn't be worth the effort. Yes, diamond is hard, but unless you have an ABSOLUTELY PERFECT crystalline structure all the way down to the nanometer scale, any flaw, even a tiny scratch, would eventually turn into a massive crack as soon as you started applying impact force. You could put a fantastic edge on a diamond sword, but as soon as you started hitting things with it, it'd crack and shatter pretty quickly.

Steel makes good swords because it's hard enough to take an edge, but soft enough to absorb impact without shattering. A major part of swordmaking is striking the proper balance between the two.

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    $\begingroup$ this should be the accepted answer $\endgroup$ May 10, 2019 at 18:05
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    $\begingroup$ @DJSpicyDeluxe nobody likes a Cassandra =P $\endgroup$ May 10, 2019 at 18:16
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    $\begingroup$ Understanding the dynamic of sword fighting would be very helpul: youtu.be/lspB3QhrW_Q?t=898 . Swords do need to be flexible: youtu.be/lspB3QhrW_Q?t=970 $\endgroup$
    – ventsyv
    May 10, 2019 at 21:13
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    $\begingroup$ You are right. Creating a perfect chrystalin structure is not possible today. Neither is it possible to control the chrystal growth so that the end result becomes a sword. But if advances in chrystal growing technology were assumed, a perfect diamond blade with a perfect edge would be a terrifying weapon. But today the idea is completely unfeasible. $\endgroup$ May 10, 2019 at 23:18
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    $\begingroup$ Is there any proof that the diamond wouldn't shatter anyway, even if it had the perfect shape down to the quark/leptons scale? $\endgroup$ May 11, 2019 at 9:42

How about a cheaper route?

The Macuahuitl, the "Aztec Sword" was pretty much a Cricket bat, but with obsidian blades inserted into the edges. If a blade cracked or was broken beyond resuse, you could just replace it.

Following that idea, you could have a wooden (or metallic) handle and middle-part of the blade, and then have a diamond edge. While this is not a pure diamond sword, you do not need to worry about micro-fractures nearly as much, and repairing this weapon is a viable option, compared to a single diamond being the sword.


In practical terms, the other answers cover the macro scale - either a brittle blade of pure diamond (maybe used only for ceremonial purposes or special executions). Or a diamond coated blade.

On a much smaller scale, diamond blades are used in laboratories, not as grit for grinding purposes - but as single atom thick (ideally, but in practice a few atoms thick at the edge) blades for slicing samples real thin - or as a diamond knife in a surgical procedure called radial keratomy (since the 1950's).

The bad-news, 6 mm wide blades (0.236 inches) start at over $2,000 each (beware - commercial link). As swords go, this is even smaller than "handy pocket-sized".


Diamonds, mostly industrial quality and not gem quality, are used for cutting. As I remember, there are diamond edged saws for various industrial uses, and the diamonds on the edges have to be replaced as they wear out.

So I can picture someone using a technological or magical sword with a chainsaw action and many tiny diamonds on the edges to improve cutting through armor or flesh or whatever.

Maybe it cuts through anything and everything at the start of the battle but as it cuts through more and more armor and bodies the diamonds crack and shatter and the edge is reduced to mere steel and it only cuts as well as an ordinary chainsaw would.

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    $\begingroup$ You'd end up with something like a Macuahuitl, only using diamonds instead of obsidian. $\endgroup$
    – Skyler
    May 10, 2019 at 18:51
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    $\begingroup$ Diamonds aren't exceptionally sharp, they're exceptionally abrasive. Great if you're cutting through a hard material like granite or steel, not so much if you're trying to cut something soft like skin. $\endgroup$
    – Mark
    May 10, 2019 at 22:13
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    $\begingroup$ @Mark: If you've ever run your finger along the edge of a diamond saw blade, you'll have realized that it is not sharp at all. E.g. lowes.com/pd/Bosch-4-in-Wet-Dry-Continuous-Diamond-Saw-Blade/… $\endgroup$
    – jamesqf
    May 11, 2019 at 4:43

Short Answer. No

Most of the detail on why this will not work is covered in this question.

While it may be possible to create a sword shaped object from diamond it is simply too brittle to be used effectively.

On a side note a sword of pure carbon would also lack the mass to be effective against a similar sized steel blade. In swordplay inertia is often your friend.

The subject of alternative materials has also been covered in this question


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