I was hopping around random wikipedia articles when I came across the article for the Behemoth. In the description for the beast it says:

His bones are as strong pieces of brass; his bones are like bars of iron

So it got me thinking, which of these three substances is hardest: iron, brass or bone?

(I had a quick look at the Mohs scale, which lists iron as 4, but could not find anything for brass or bone.)

  • $\begingroup$ Please note that the general meaning of "hardness" is much broader than the Mohs scale, which basically measures "resistance to scratches". Hardness includes ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity (list copied from Wikipedia), all of which have specific meanings and little to do with Mohs hardness. $\endgroup$ Jul 24, 2016 at 8:28
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    $\begingroup$ There is quite a difference between a strong material and a hard material. $\endgroup$
    – Johannes_B
    Jul 24, 2016 at 10:39
  • $\begingroup$ en.wikipedia.org/wiki/Strength_of_materials $\endgroup$
    – Johannes_B
    Jul 24, 2016 at 10:45
  • $\begingroup$ @GuntramBlohm I think if I asked for all those things the question would be closed as too broad. $\endgroup$
    – Pharap
    Jul 25, 2016 at 0:45
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    $\begingroup$ Thought this was interesting: Modulus of rigidity. Bronze is higher than iron which raises a question. Why did iron tools replace bronze tools. Suspicion: iron is more flexible (less brittle?). (Some sources saying that the problem with bronze is the need to make an alloy, but no advantage in the edge, hardness or moduli. $\endgroup$ Dec 17, 2016 at 2:18

1 Answer 1


These two sources both put bone at a hardness of 5:



Whether they are trustworthy is questionable though, so take it as you will.

This source put brass at 3 and iron at 4.5:


and this image puts brass at 4 and iron at 4-5 (Similar to 4.5): http://patentimages.storage.googleapis.com/WO2001048807A1/imgf000009_0001.png

While these different sources seem to have conflicting data, I think it would be safe to assume that Brass is the softest of these three materials, Iron comes second, and Bone is the hardest.

Edit: In the description of that monster, the adjective used is 'strong'. You may want to consider how much force each of these materials can withstand instead of how hard they each are :)

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    $\begingroup$ Bone is primarily composed of hydroxyapatite. Note that the apatite minerals define the value 5 on the Mohs scale. $\endgroup$
    – f''
    Jul 24, 2016 at 6:31
  • $\begingroup$ Right; the composite material (bone) is much better for load bearing vs weight, and scratching it is not an issue. $\endgroup$
    – JDługosz
    Jul 24, 2016 at 9:09

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