It's not just about the values, it's how they're going to contribute to the equation. A saguaro (cactus) spear hits a fluffy wambler bone shield. What do? Trick question. Fluffy wamblers don't have bones.
(15 tabs and a few hours later, I did some deductive
!SCIENCE! and
!Pondering Material Qualities!)
I've been reading up on the specifics of this, and it's going to be kind of hard to do these "accurately" without doing calculus to get everything precise and accurate, although we don't need these things to be precise, nor accurate, being this is a game.
The one major thing I find missing after going through the raws to make this work, is a definition for actual material strength. There are definitions for bending, torsion, tensile, and compression yield/fracture, but as far as I've seen those material factors either don't do anything, or they might do something in relation to shot blockage or armor penetration. It's hard to !Science! this since other factors will always be included.
I know what the term yield is supposed to mean. It's supposed to be how much energy is imparted into the location when impacting something at maximum material usable force. The term I'm not sure what means is fracture. I don't know if it's supposed to imply blunt force damage, or something else, such as the point in which the material is supposed to break, which would be more sensible.
Comparing copper to candy for example.
Candy has a value of 3000000 for each of it's fracture values making it near unbreakable, being the highest value of any weapons grade material.
Copper has different individual values. Impact being 770000, which should mean it would be reasonably hard to break when struck although this is just a "general" number.
Compression being 770000, same as the above, implying that if it's compressed, such as while stabbing, or being used to block a blunt object, such as a hammer it would break as easy as a standard impact.
A Tensile value of 220000, which should mean if pulled on too hard, it would break easier than if compressed or banged against i'm not sure how tensile strength would be tested in this game though, not much likes to keep whatever stabbed it inside them, and I don't think a tug of war over a spear would work out well either.
A Torsion fracture value of 220000, same as the tensile value, meaning if twisted, it should break the same if pulled with the same quantity of force. We don't have twisting of weapons yet, but imagining someone stabbing a metal body FB, and twisting hard enough, they could break their weapon.
Shear strength of 220000, which would actually be most applicable in the instance of a spear, since the basic equation for this one is force/surface area, spears having relatively high force, and low surface area. It could be reasonably easy to blunt a spear. Considering early Roman Legionaries used javelins that did specifically this when thrown, the javelin bent on impact with the victim making it near impossible to remove.
Lastly there is the Bending fracture value of 220000, which would be applicable if, for example, using the flat of the sword against something highly resistant to compression impact.
Of course after all of that there are values for strain at yield, which are different for every material in the game, candy experiencing none, which applies when the weapon reaches the named "yield" value, which I assume would be the most "optimal" point in which all the objects usable force is actually used. The wiki says it's used for blunt and edged combat, being the same thing as elasticity, and a lower value here is better, which should be a given, bending is bad. This leads to a different set of contradicting values.
Copper has an Impact Yield Strain of 175, which is one of the highest values of this type of metal. If it were to be used at full power, this weapon material has a very high chance to do something in a generic "impact".
A Compression Strain of 175 would in theory mean that Copper is one of the best stabbing materials short of steel or candy.
A Tensile Strain of 58, which is actually pretty low, although the material itself is weak against being pulled apart, it doesn't bend much while being pulled. Technically, this weapon material would snap before it bends it put into a tensile test (which again could be great for things like arrows if being pulled out was relevant, leaving a piece of the weapon inside for the !FUN! that comes with infection).
A Torison Strain of 145, which should mean this weapon would be fairly hard to bend in a twist compared to most other weapons grade metals. Although we currently can't twist embedded weapons (that i'm aware of) copper would do it quite well being reasonably resistant to twisting.
Shear Strain of 145 which makes it a decent type of armor, fairly resistant to denting, as well as a decent blunt weapon, for the same reason.
Lastly the Bending Strain of 58 means it's actually pretty hard to bend this weapon, but like with Tensile Strain, it would lead to a high chance of a snap if attempted to bend too hard.
To be honest, after looking over what I've been compiling for the last few minutes, writing this up.
TL;DR
Copper is arguably the best "conventional" weapons grade metal short of Steel and candy for edged weapons/armor, and silver for hammers.
In response to your question Bumber. I have no idea, it involves calculus depending on how accurate Toady wants the game to be. I was never any good at calculus. The thing is, all of the things we need are here. My brain just hurts too much to do the maths.