How good could magically hardened bones get for weaponcraft

Question

I haven't used tag "magic" because while the process is magical, I am interested in resulting material, which is itself completely unmagical and follows physical laws of our world.

So, I have a problem. My magic civilizations are due to reasons magical unable to use most metals in pure form or as alloys for most typical uses, only being able to use their compounds[read rocks]. Instead, some of them are able to refine organic material, and for example alter its shape or join it together similarly to how smiths can smelt. They mostly use bones and wood as materials for their weapons. I already have wood covered(found out about densified wood), now I need to focus on bones.

While metalwork is not in use, they're able to alter the material to some extent. While the process of alteration is magical, the result of the process isn't. The material simply changes its structure or content, and there is no sustained magical effect after the process is over. They can't(at least not yet) do anything as drastic as produce nano materials, but they can remove things that were useful for a bone in a living organism, but are bad for bone as a material.

List of all restrictions:

• no nano-materials

• they can remove things that were useful for a bone in a living organism, but are bad for bone as a material(marrow, microholes for blood flow, etc.).

• they can alter composition by removing material to make the quality better (it is possible to remove some of the calcium or colagen, but it's not possible to replace them with something else like metals).

• they can introduce new organic materials(not in the meaning of organic chemistry, but in meaning recently originating from organism, such as shells, teeth or recently cut wood, but not anything that was abandoned by the organism years ago) to the bones. (Yeah, I've read about limpet teeth and I do plan to use that, but only for extraordinarily expensive weapons for nobles, as it is a rare material in my setting, but I also need standard weapons for common soldiers)

So, How much can bones be improved as a weapon/armour material under these restrictions?

Answer 1

Good is a relative term, but weapons and armour are relative things anyway.

Bone and stone tipped spears are good enough if all your opponent has is bone tipped spears but not if they have bronze. Bronze is good enough if they don't have iron. Iron is good enough if they don't have steel. etc.

So how good can bone be? It doesn't matter if that's the best anyone can have. If someone is better at making bone harder than you are then you'll struggle, but it remains a relative factor. Any bone is good enough to pierce flesh.

Limpet teeth (5GPa) are stronger than flint (600MPa, 7 Mohs Hardness) in the headline values, but the two are not directly comparable as the value for limpet teeth is tensile strength and for flint is single axis compressive strength.

Teeth and bone (both around 5 Mohs hardness), tusks (2.75-3.50 Mohs), and horns, all tried and tested for penetration weapons, and all come behind flint as a primary option for weapon tips, but bone is easier to work. (Claws come in at a mere 2.5 on Mohs, horns I can't find a value for.)

So no matter what you do with bone, it's likely flint will still be a better option.

Answer 2

I think their ability to craft good weapons out of bone-material depends entirely on how fine structured shapes the can produce and how much they can learn from natural bone structures.

Bone is not stronger than rock, so solid blunt weapons (like hammers or maces) made from bones will likely never outshine rock counterparts. However, natural bones are not a solid chunk of material, instead - especially the strong adult bones that mostly consist of lamellar structures - bone is organised into a lot of parallel fiber structures that distribute material stress and strengthen material in one specific direction, this is why bones can easily hold (much more) than your weight if you stand on them, but moderate force applied from other angles can break them.

This allows bones to be both flexible and/or light while still being quite strong for their intended/necessary purpose. If the magic shaping the bones allows your people to understand and more importantly recreate these features they should be able to create weapons that are exceptionally light and strong at a single point (good for piercing arrow heads or spear tips, maybe inspired by bird bones) or flexible but strong along the edges (good for slashing weapons like swords or scimitars).

Answer 3

First let's get one thing out of the way. Bone material and density varies a lot from animal to animal, so you can't just pick up a hawk bone and expect it to have the same properties as a dog bone. So what creatures have the best bones?

Luckily the animal kingdom is full of creatures with strong bones. Think large and sturdy animals like cows, horses, even exotics like rhinos (which may have the strongest bones out there). So let's source our bones from slaughter animals, because they're already getting killed for food and leather.

Now that we have a strong animal bone to begin with (I'm assuming cow or horse femur would be a great start), let's look at the composition. Animal bones are mostly collagen and calcium phosphate. Collagen is the soft part, but according to those sources it is also necessary to make bones flexible and durable, so maybe we should leave it. You don't want a weapon to be too stiff or it will break. So what else do we have to work with? Well, the internal structure is spongey and full of marrow, so there's an opportunity.

Let's take your example of metal compounds (rock). Your mages could translate the marrow into a metal-dense stone for added weight and core strength, leaving the outside bone to provide the structure and a surface from which to carve an edge.

This would make bludgeoning weapons very easily, and with someone to shape the bones into blades you could end up with some interesting-looking swords. Take a look at the images in the second link and try to picture what it would look like shaved into a flat blade with a solid core.

All that being said, weapons made from the strongest bones (like rhinos) could be very sought-after, leading to poaching like we have today.