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Imagine a world where only precious metals are available. They are as common and plentiful as iron or aluminum are in our world. Any metal that is not precious does not exist outside of biological forms, like the iron in our blood.

Taking this into account, which metals, or alloys, would be the most used for tools? Things like axe heads, pickaxes, knives, etc.

For the purpose of this question, let's use the wikipedia's list of precious metals: https://en.wikipedia.org/wiki/Precious_metal#Rough_world_market_price_($/kg)

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  • $\begingroup$ Comments have been moved to chat; please do not continue the discussion here. Before posting a comment below this one, please review the purposes of comments. Comments that do not request clarification or suggest improvements usually belong as an answer, on Worldbuilding Meta, or in Worldbuilding Chat. Comments continuing discussion may be removed. $\endgroup$
    – Monty Wild
    Commented Aug 17, 2023 at 4:53
  • $\begingroup$ does this include ALL precious metals, are osmium, rhodium, ruthenium, iridium all on the table too? $\endgroup$
    – John
    Commented yesterday

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Palladium White Gold

Jewelers have spent centuries learning to alloy precious metals in ways that make them strong enough that they can include tiny details without being too delicate.

While pure golds (24k) are soft and delicate, but golds between 14k and 18k are a lot tougher than most people give them credit for. Cast gold is usually used in jewelry making meaning that lower karots are often needed to get desired hardness and toughness, but like bronze, these are typically work hardened alloys. If you were to cast a typical 18k gold, and hammer it into a blade or armor, the resulting alloy would have a hardness and tensile strength slightly better than a 1055 rolled medium carbon steel.

The ideal gold alloy for this is a mixture of about 75% gold, 20.5% copper, and 4.5% silver. Unfortunately, Copper is not on the list given by the OP (despite being on many other precious metal lists); so, we need to look to other gold alloys with similar properties if we want to meet the OPs specs as asked.

This is where the palladium comes in. Palladium is sometimes used to substitute for copper or nickel in gold alloys because it gives a similar hardening factor when caste while also being hypoalergenic... but unfortunately, it does not work harden like copper gold alloys. Instead jewelers add Ruthenium to Palladium Gold alloys until it reaches its desired hardness. This alloy wont be quite as durable as a work hardened copper-gold alloy, but it can get pretty close. The resulting alloy should be about 60% gold, 15-20% silver, 15-20% palladium, and 5% ruthenium, and you will be suitable for a wide range of tools using only the elements on the OP's list

Ultimately, the resulting alloy will be just as tough as a lot of the weapons and tools made throughout most of the iron age, but the metal will be more dense and heavy. So, you will likely see a lot of shorter weapons and tools. A gold alloy gladius or kopis might work even better than early steels because the higher density will give you more power without broadening the blade profile, but don't expect any long swords or full plate armor since the increased density would make those prohibitively cumbersome.

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    $\begingroup$ Thanks! I was reading about an alloy 80% platinum and 20% iridium, but I don't know how that woulc compare to your gold alloy $\endgroup$
    – Rhomaioi
    Commented Aug 15, 2023 at 15:15
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    $\begingroup$ @Rhomaioi They come close. A lot of it has to do with the exact amount of ruthenium you add, but in general, Platinum alloys tend to be a little bit more scratch resistant, but gold alloys are more resistant to crushing and deformation. Most tools should be better with gold alloys, but I suspect platinum alloys should have their ideal use cases as well. If you allow copper, then the work hardened gold alloy should be by far your better option though. $\endgroup$
    – Nosajimiki
    Commented Aug 15, 2023 at 15:21
  • $\begingroup$ A gladius weights around 700g, so a gold gladius would be about 1.65kg. A long sword would be 3.25kg (up from 1.3). So that seems about right, though even a gladius might be too sluggish, there is no point in a shiny metal weapon when some dude with a stone axe (or just a wooden spear) destroys you because he is so much faster with it. I guess for weapons and armor in general these heavy metal alloys are of very limited usefulness. Maybe spear and arrow tips. $\endgroup$
    – LazyLizard
    Commented Aug 15, 2023 at 17:01
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    $\begingroup$ @LazyLizard plenty of 1 handed weapons were ~1.65kg. Heavy weapons are easier to control when they are shorter; so, while you generally don't want a 1m long sword to weigh much over 1kg, shorter weapons can get away with it much more easily. $\endgroup$
    – Nosajimiki
    Commented Aug 15, 2023 at 18:25
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    $\begingroup$ @Rhomaioi I was not able to find an exact material properties list. This information was pulled from a lot of incomplete sources. Some properties I could not find exact values for, but from browsing jeweler making forums, I could determine many properties as somewhere in between 2 other metals that I could look up. Just explaining how these values were derived would probably triple the length of my answer. $\endgroup$
    – Nosajimiki
    Commented Aug 16, 2023 at 13:41
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Beryllium, all over the place...

Beryllium is not even remotely related to what most people consider to be a precious metal, but it’s on some lists of precious metals (including the one the question states to use as a source) for two major reasons:

  • It’s comparatively rather rare. Not as much as the platinum group metals or gold, but enough that it’s abundance within the earth’s crust is best measured in parts per million.
  • It’s absurdly useful stuff.

Beryllium is actually a surprisingly good structural material. It has a rather low Poisson ratio, a bulk modulus not much lower than steel, a shear modulus and Young's modulus much higher than steel, and a lower coefficient of thermal expansion than steel. It’s also reasonably hard without being too hard to be useful, and has an absurdly low density for a metal (1.85 g/cm³, compared to 1 g/cm³ for water and about 7.85 g/cm³ for typical steels).

Of the metals on the list being used here, beryllium is the single most useful option, and it will be used almost everywhere.


Other things to note:

  • Hammers and other things that need to be heavy will probably use platinum or a platinum-iridium alloy.
  • Osmium-iridium alloys are likely to be used for things where weight is negligible or does not matter, but durability is super important. They even beat out tungsten by some measures of durability.
  • There will be no real replacement for applications we currently need super-hard materials like tungsten carbide for. You simply cannot get to that point using just the metals on the list.
  • Copper is going to be super valuable here for a number of reasons.
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    $\begingroup$ However beryllium is toxic, reactive and brittle, so it will be a challenge to manufacture something out of it. $\endgroup$
    – LazyLizard
    Commented Aug 15, 2023 at 13:05
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    $\begingroup$ @Tristan - and a large enough supply of fresh people to offset dying from lung issues caused by berylliosis. $\endgroup$
    – Jon Custer
    Commented Aug 15, 2023 at 15:41
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    $\begingroup$ @JonCuster throughout history people have used tools that killed them or the people making those tools. That's far from prohibitive $\endgroup$
    – Tristan
    Commented Aug 15, 2023 at 15:53
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    $\begingroup$ @LazyLizard Could life in a baryllium rich world have evolved to be come tolerant of it? $\endgroup$ Commented Aug 15, 2023 at 18:34
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    $\begingroup$ The other thing about Beryllium is that it is too light for a lot of tools. Hammers, axes, etc use the weight of the steel in them to deliver force. I imagine most tools would use a Beryllium jacket over a more dense core metal. $\endgroup$
    – Nosajimiki
    Commented Aug 15, 2023 at 19:19
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Eternal Stone Age or Advanced Space Age


None of those metals on their own are particularly good for use as large tools. Gold doesn't make a very good axe and silver doesn't make a very good weed whacker blade. So, absent any kind of cool alchemy, people would most likely continue on with tools fashioned from stone, wood, laminates, bone, etc. Small tools, like surgical instruments, spectacle frames, weights, food vessels and so forth are all viable contenders for being made from almost any precious metal. (Would stay away from gallium dinner plates, though!)


However, if you allow for curious alchemies, there are alloys of precious metals that could prove to be viable in tool making. One could argue, perhaps, that the concept of mithril, hard as steel, lustrous as silver, is just such an alloy.

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    $\begingroup$ Copper was the first metal in common use. Mix it with other metals and you have bronze which is surprisingly useful. The Egyptians used copper and bronze tools to carve all sorts of stone. $\endgroup$
    – David R
    Commented Aug 15, 2023 at 14:03
  • $\begingroup$ @DavidR 954 aluminum bronze is like mild steel except it doesn't rust or gall. However OP did specify "Any metal that is not precious does not exist outside of biological forms, like the iron in our blood." $\endgroup$
    – DKNguyen
    Commented Aug 15, 2023 at 14:29
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    $\begingroup$ The trouble with answering this, is we have never explored the metallurgy of mostly-precious alloys as (say) steel or brass replacements. For example, Scandium (which many folks will never have heard of) is normally used as a fraction of a percent to harden and strengthen Aluminium. What would majority-Scandium alloys be like? A bit like Aluminium, a higher melting point, but we know no details. Hafnium is similarly used to transform steel into turbine blades, again in small percentages. $\endgroup$
    – nigel222
    Commented Aug 15, 2023 at 14:33
  • $\begingroup$ @DavidR --- Copper isn't on the list and doesn't comply with the query. Obviously, if copper is available, then copper (or alloy) tools! $\endgroup$
    – elemtilas
    Commented Aug 15, 2023 at 22:33
  • $\begingroup$ @elemtilas -- The article containing the list does specify copper as a coinage metal, so I would allow it. WP is not a primary reference, after all. $\endgroup$ Commented Aug 16, 2023 at 14:44
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If Iron is available in biological forms, it could make for quite grim stories of harvesting it.

There might be ceramics (you might want to avoid the most obvious one, BeO, due to its horrible toxicity...) and amalgams based on only precious metals not known to our science because nobody looked hard enough, for lack of a practical application.

And do not underestimate good old carbon... as diamond, or carbon nanotubes, it could be useful in quite many tool applications.

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  • $\begingroup$ since a person is born with all the iron they will ever have, babies will be an excellent source. $\endgroup$ Commented Aug 16, 2023 at 0:13
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    $\begingroup$ @RockyRococo That's entirely false. You process a fair amount (in biological terms) of iron through your system on a daily basis in the form of dead blood cells, replacing the lost iron with iron from foods rich in the stuff: leafy greens and red meats. $\endgroup$
    – Corey
    Commented Aug 16, 2023 at 21:50
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While a world that follows the premise of the question has serious issues to face, just going along with it, I think you might find this wiki page helpful.

Hardnesses of the Elements (data page)

In such a world there would be alloys that we've never even thought of trying to make, and they would likely find some alloy that solved their problems. However, if we're sticking with pure elements, of particular note is rhodium, the first element on your list of precious metals, which has a Brinell hardness of 540, comparable to abrasion resistant steels used in the mining industry and much harder than things like cast iron or even tool steel. It is also durable, so it doesn't wear easily. It's a noble metal, and like all of that family is is very non-reactive.

It's not perfect, of course. Its biggest drawbacks are that it is brittle and that it has a high melting point.

I don't know if anyone has ever simultaneously possessed enough rhodium and had the desire to make a hammer or axe head out of it. In its pure form it can't be made into good jewelry because it's tool brittle and the jewelry breaks. That said, a large lump of it is a different question, and it would definitely be possible to chop down a tree with an axe with a rhodium head. Breaking rocks? The pick/hammer might shatter or chip, depending on the hardness of the rock. However, again, it should be comparable to AR steels, and they're used for mining purposes.

It melts at 1538°C (3565°F). This is above the temperature that a coal/air forge can reach, so it couldn't be cast using coal to melt it. To be clear, it would be able to be heated to workability in such, and since it is typically found as an uncombined metal (like gold, basically) it should be able to be forged into a lump and then further into whatever shape is needed. It is apparently quite difficult to machine - there are numerous machinists complaining about it ruining their tooling on forums.

Neither better nor worse really, but worth considering, is that it is also ~1.5 times denser than iron, so any tools would be heavier (or smaller).

Finally, if weapons are a consideration, it would be fairly awful for most of them. It would potentially make a ferocious projectile weapon (arrowhead or bullet, that is) but a large, chunky sword or axe would be too heavy for human scale muscles to use effectively and a thinner weapon would be too easy to shatter. I guess that might actually pose an interesting challenge to duelists - not quite as bad as fighting with glass swords, but a similar idea.

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