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A Guide To Metals & Some Of Our Top Most Durable Watches

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles

Article by Matt Reudink

Inadvertent smacks against a doorframe, accidental scrapes against a concrete wall, or the errant slip of a spring bar tool. These simple and often inane mistakes can result in frustrating, disappointing, sometimes anger-inducing and yet seemingly inevitable scratches on originally pristine watches. This sad fate does not, however, have to be the case – as we detail here, some watchmakers use special metals and surface treatments that greatly reduce scratches and keep your watch looking like new. There are a few ways to achieve extra durability in a metal – and those are discussed below. Along with examples of watches and companies that aBlogtoWatch editors feel make some of the best examples of hardened or treated metal watches. 

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles

While some of us may embrace wabi-sabi, letting the dings and scratches tell a story of a life well lived and a watch well worn, others of us are less Zen in our approach to watch ownership, preferring that factory-fresh finish and lamenting each new scratch. Luckily for us, horological metallurgists have been dreaming up new compounds and treatments that can result in extremely hard, scratch-resistant cases that can endure even the clumsiest of owners.

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles

While some companies are innovating the use of completely new materials (e.g., Rado’s DiaStar and ceramic compounds), the majority of super-hard watches utilize steel or titanium as the base material. How exactly companies achieve increased hardness and durability is variable, but generally falls into three categories listed below. Regardless of which you choose, the result is a watch that will better resist the scratches and dents that result from an active (or clumsy) life. In some cases, these watches will retain a “brand new look” for many years to come. 

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles

To put this discussion into context, let’s first examine differences in hardness among some common watch materials. To measure the hardness of a given material, scientists have developed a number of different metrics, including the Brinell, Rockwell, Knoop, and Vickers hardness tests. For watch materials, the results of a Vickers hardness test are commonly reported, providing an HV value – a unit of hardness that describes a material’s ability to resist deformation from a standardized source. The higher the number, the harder the material. Listed below are typical values of common watch materials: 

316L stainless steel: ~150-200 HV
Titanium: ~350 HV
Gold: ~140 HV
Zirconium oxide ceramic: ~1200 HV
Sapphire crystal: ~2200 HV
Diamond: ~10,000 HV

For case materials like steel, titanium, and even gold, additional steps can be taken to transform or modify these relatively soft metals into harder materials better able to withstand bumps and bruises brought on by daily life. The primary techniques employed to achieve this increased hardness include: 

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles

Hardened Steel Alloy

316L stainless steel is ubiquitous in watches. It is a strong, corrosion-resistant alloy comprised of iron, chromium (16-18%), nickel (10-12%), and molybdenum (2-3%) and has a hardness of roughly 150-200 HV. By altering the compounds in the alloy, watchmakers can change how the metal itself can be treated and its resultant hardness. For instance, by removing nickel and adding carbon and nitrogen in a proprietary process, Damasko can harden their steel to 800 HV, roughly quadruple the hardness of 316L steel. Sinn and others utilize “submarine steel,” or HY-80, an alloy similar to 316L, but with less nickel and a low carbon content. Though only slightly harder than 316L (~300 HV), this steel is highly corrosion resistant and used in dive watches subject to frequent immersion in salt water. Overall, these alloys are hard, scratch-resistant, and offer a unique, deep, nearly titanium hue. 

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles

Metal Surface Hardening

Besides the difficulties in manufacture, one disadvantage to hardening steel is the potential to create a brittle alloy. As a result, some manufacturers utilize surface-hardening treatments. Though they may go by different names (e.g., tegimenting [Sinn], ruggedizing [Mercer], EBE2000 [Bremont]), all describe processes that harden only the outermost surface of the metal. The hardened layer may only be micrometers thick, but it is extremely hard and scratch-resistant often at ~1200 HV or greater. An advantage of this approach is that it can also be applied to different metals, such as titanium and even the above-described submarine steel. A downside, however, is the potential for a hard (very hard) impact to result in an eggshell-like crack by bruising the metal under the coated layer. 

A Guide To Metals & Some Of Our Top Most Durable Watches Featured Articles


Another approach used by several prominent companies is the use of super-hard, scratch-resistant coatings such as Seiko’s DiaShield or Citizen’s Duratect (though note that Citizen uses both coatings and surface hardening treatments). Similar to DLC (diamond-like carbon) coatings, they are specifically designed to improve scratch-resistance. Seiko’s DiaShield has a reported hardness of ~500 HV, while Citizen’s different treatments range from 1000 HV to a staggering 2500 HV. As with any hardening approach, one challenge is that if a scratch does occur, any polishing or repair will be extremely difficult. Regardless of which technique is used, one of our favorite aspects of hardened watches is their accessibility for almost every budget, from relatively affordable entry-level pieces up through many-thousand dollar watches. Below, we list nine examples of watches that utilize these hardening techniques. Chime in below in the comments to let us know your experiences or pieces we missed that you think should be highlighted. 

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  • Victorinox INOX?

    • Ulysses31

      The fact that it comes with a plastic shield gives the impression that it is not that durable, contrary to the marketing.

  • What fresh hell is this?

    I’m quite partial to melodic death metal and extreme progressive metal myself.

    • Berndt Norten

      Careful now—metal health will drive you mad!

      • egznyc

        Bang your head. But not your watch … unless it’s hardened steel. I’ve always been partial to come on feel the noise, and always wanted the girls to rock this boy.

  • ??????

    Thank you for this fantastic article, it gives the answers i’ve been looking for for a long time. I wonder why not all brands and models utilize these incredible, game-changing metal treatment techniques. I see a good deal of hypocrisy and disrespect for their customers here. Rolex, Omega, your move

  • Lincolnshire Poacher

    Great article. I like it when abtw aproaches watch collecting from differnt perspectives.

  • SuperStrapper

    Love that magic gold. The industry’s coolest alloy? Maybe.
    And while I don’t mind the colour, I do look forward to them release colour updates to the material, which I have no doubt are in development.

    • Dimman

      It’s not an alloy, it’s a mixture. It gets the hardness from the carbide content. It’s 18k because it’s 25% carbide content and 75% pure gold. That means they are limited to the weird yellow colour unless they go down in karat. However they could experiment with other precious metals such as palladium or platinum for non-yellow, but those need to be .900 or .950 to get a proper hallmark, so it probably won’t be happening either.

    • Stewart Novinger

      I like the durability that magic gold offers, I just don’t like the color, I wish they could get it to look like 4N or 5N rose gold.

  • SuperStrapper

    I still find it off that no one has tried case hardening. Not only does it give sure a unique and interesting appearance that could do quite well with the right watch, but proper technique yield results in the same rating categories as some of these pieces.

    • Matt

      My understanding is that 316L cannot be hardened by heat treatment, so full case-hardening (like Damasko) requires a different alloy with added carbon. Finding the right alloy to work with seems to be a series of trade-offs (hardness, corrosion resistance, brittleness, color, difficult to work with, etc.). Regardless, I’m all for innovation and experimentation here!

    • A few years ago Bulova mdke a 24k gold case that was supposed to be relatively hard – they used a forging technique as I recall.

      • SuperStrapper

        The Percheron. I was just discussing it then other day (different subject).
        On that watch, I dont know what ‘forging’ means in the description they provided or that I’ve seen. I seriously doubt it is a heat forge, and assume a cold forge technique where a lump of gold is basically smashed into shape cold, slightly hardening it. The percheron case is a composition of parts and the gold ones could be cold stamped gold that is technically cold forged. They would be harder than gold but still not anything like entry grades of steel: I doubt it doubles its hardness, otherwise why not state as much.

      • Spangles

        There’s also the Charles Frodsham Double Impulse Chronometer with a George Daniels movement. They have an option for a 22k gold case which they say is the same durability as 18k due to the way it is processed (cold rolled or something).
        It’s an interesting watch, surprised not to see anything on ABtW on it (paging Ariel).

    • Joel Schumann

      Hmm. Interesting thought experiment. I mod watches occasionally and I have made some knifes too. I guess I could put an Invicta or Seiko case in the forge next time. I was actually surprised that the steel of a watch case is, relatively speaking, quite soft (compared to hardened tool steel for instance). If you put the case in the forge just like that, it will give an interesting appearance for sure. My knifes are made like that, and then I have sanded down to the steel, leaving only the worst scars. I would be curious to see how it matches a blue sunray dial for instance – could be an interesting contrast there.

      I don’t really need hardening, though. None of my watches have scratches, despite using them in all kinds of “adventure” activities.

  • Stewart Novinger

    What about the SS that Rolex uses? I believe it is 904L SS? Is it harder than 316SS?

    • John Mark Booc

      afaik, they have same hardness, difference is the corrosion resistance only.

    • SPQR

      As stated the same hardness but there is more nickel in 904L than 316 so it is not good for allergy sufferers. The alleged better resistance to corrosion is really only to sweat/saltwater over an extended period of time in certain circumstances so you would notice the difference over several decades provided you did not flush the saltwater off the steel after immersion in the sea. Other than that little to no difference. So “Oystersteel” is just “Steel”. Rolex’s marketing department strikes again.

  • Tempvs Mortvvs

    What about Ventura’s hardened steel and titanium – durinox and titanox? They are superb treatments that allow a watch to look like new for many years. 13 years for mine so far. I also think they were pioneers in that regard.

  • Raymond Wilkie

    One scratch and it’s gone.

  • Tony NW

    The email notification for this article featured a photo of the Seiko Presage. Which is ironic, because largely Seiko makes among the LEAST tolerant watches for abuse, even in the Presage line. That particular Presage has a sapphire crystal, but mine, the SARB065 (“Cocktail Blue”) has their barely-reinforced plexi Hardlux on it. And, as happens with those got scratched nearly immediately. In my case, while UNDER a shirtcuff, I got too close to a rental car trunk latch. The metal hit my shirt cuff, not the watch, but left an impact mark.

    The SARB065 does have sapphire, but generally you should warn buyers away from Seiko if they want durabilty. (Of course, at the price, you can buy another Seiko for a lot less than the regular servicing cost of a Rolex.)

  • Mark

    Thanks ABTW for publishing Matt Reudink’s article. It is a nice basic foray in the different things that manufacturers do to make the cases more scratch resistant. And managing not to go down any rabbit holes. We as consumers want a product that will look as good twenty years from now as it does when we first opened the box. Some manufacturers would like to give us a product that could, but in the end it becomes value vs cost.

    • Ariel Adams

      Mark, we are glad you liked it. Matt and I worked on a series of drafts for this article so this is really a collaboration as many of our articles are. He brought up interest in covering durable watches and the concept evolved into this. Thanks for recognizing the effort we put into this content.

  • Dimman

    Alloy is a solution. The Carbide doesn’t dissolve in the gold. Not an alloy.

    • Kuroji

      You’re wasting your time. Strapper always does this. He cannot be reasoned with.

  • Abdul Kalik Abdul Razak

    Any watch made in tungsten? I’ve been searching for a tungsten base watch to no avail.. It’s heavy, but I’m a man, so no issue with weight ???

    • SuperStrapper

      Many actually, in several ranges of affordability. A few lesser known but strongly followed brands released tungsten cased watches, like LumTec and U-boat, the former of which also had a full tungsten bracelet.
      Rado is likely best known for their work with tungsten carbide and high tech ceramics.
      There is a massive glut of no name fashion brands watches claiming to be tungsten, I’d avoid them all. Not worth the risk and they’re basically all mall watches anyway.
      Android, which I think may be an offshoot of invicta, also released a bunch of tungsten watches with automatic movements but I would avoid those as well.
      In the vintage space, there was that weird Seamaster from the 70s, the “giant” that had a steel case “hardened with tungsten”. I never did get around to fully investigating what that means…

      Anyway, it shouldn’t be overly difficult to find a tungsten watch, although lately the material doesnt seem to be holding on to much interest as ceramics have evolved.

      • Abdul Kalik Abdul Razak

        Thank you kind sir..

      • Kuroji

        In my experience the items described as being made of tungsten are nearly always a “hardmetal” alloy composed primarily of tungsten carbide.

    • Johan

      The omega globemaster features a tungsten carbide bezel

      • Abdul Kalik Abdul Razak

        Thank you kindly..

    • Kuroji

      Never seen one. There’s a bunch that use cemented metal carbides (hardmetal) based on tungsten carbide in a nickel matrix.

  • al-nitak

    an artificial diamond coating shouldn’t be so highly expensive nowadays, I guess…

  • Bozzor

    Can vouch for Citizen Duratect ? (alpha), the highest level of their Super Titanium metals: up to 2,500 HV. You have to be working regularly with high abrasive substances to even have a minute chance of scratching a watch using this tech.

  • anonymous

    There’s got to be something better than diamond. Can’t we have watch cases out of neutron star material?

  • Matt

    Good point – the Oceanus line also has some hardened watches.

  • G Williams

    I admire ABTWs attempt to tackle the tough questions. This time they really waded into it. Hardenss is notoriously difficult to compare. The main issue is that differnet ranges of hardness require a different test so Vickers does not correlate directly to Rockwell and Rockwell B does not correlate directly to Rockwell C and so on. Then there is the vast number of alloys that are all called “steel” and the fact that different treatment during production affects hardness. This is why a fairly quick Google search will often pull up a wide range of numbers of any given material.

    There is no question, though, that specific hardening techniques will improve hardness so the overall message if the article is on point. The only thing that looks off are the gold vs 316 hardness numbers. I do not think that jewellery gold is ~93% of the hardness of 316 steel. A quick search suggests it is closer to ~50%.

    • Dimman

      Gold has a pretty wide range of hardness depending on alloy and treatment. In the past the wealthy had fruit knives with gold blades.

      • WINKS

        …so the blade wouldn’t oxidise.

  • Spangles

    Diamond is hard, but can fracture.
    Nephrite Jade, for example, is much easier to scratch, but is a much tougher material in terms of fracture.

  • Joel Schumann

    I’ll get back to you. I have a few other ideas that might have higher priority right now, so unless Ariel donates a Seiko it might take a while. I like the idea of joining in on a project.

  • egznyc

    Diamonds Are Forever, right?

  • Gokart Mozart

    I can wear it ;).

    That’s as far as my technical watch skills go.