# Hardlex vs Saphire



## redryder (Dec 13, 2007)

Is the Seiko hardlex crystal good? How does it compare to a saphire crystal?


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## ksv123 (Mar 8, 2007)

I think it all depends on how it is hit or scratched.
I have both and the sapphire has a small scratch and the hardlex has a pin hole size ding.

There is alot of info out there on this debate.

I would not halter on either, so don't let it make you not buy a specific watch.


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## ksv123 (Mar 8, 2007)

here are some links

http://www.larrybiggs.net/scwf/index.php?mod=103&action=0&id=1037842045

http://www.larrybiggs.net/scwf/index.php?mod=103&action=1&id=1176221491


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## Angelis (Feb 12, 2006)

From what I have heard:

Sapphire crystal is expensive (especially the thicker it is), but it is not impact resistant. It is HIGHLY scratch resistant, not scratchproof.

On the other hand, mineral crystal, even Hardlex, is very impact resistant, but less scratch resistant. Ideally, a thick curved sapphire crystal is best, but SO expensive. I'd settle for a thick curved minearl crystal.


Angelis


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## Isthmus (Feb 13, 2006)

The second link Ken posted above really goes a long way toward explaining the differences and dispelling the myths surrounding sapphire crystals versus hardened mineral crystals. Read it and if you still have any questions we'll be glad to help answer them.


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## Angelis (Feb 12, 2006)

The most critical info from the second link, IMHO, as quoted from this link: http://www.larrybiggs.net/scwf/index...&id=1176221491

_A LITTLE INFO. ON WATCH CRYSTALS:

There are four main types of crystals that concern us here: Sapphire, Seiko Proprietary, Acrylic & glass.

Artificial sapphire (as is used for watch crystals) is grown in a crystal lattice, unlike the flame-formed sapphire, like the kind you find in common graduation rings. The Sapphire crystals used in the overwhelming majority of watch crystals are artificially grown (in a boule. Once formed, the boule is then sliced and the pieces are then cut and polished to the desired shape. This material is very hard an resistant to scratches from common every day use, but it is also (like diamonds) brittle and has a tendency to shatter on impact (provided the impact is just right). Flame formed sapphire while chemically identical, lacks the internal crystalline structure and is much softer and brittle.

Hardlex is a Seiko proprietary type of hardened mineral crystal and comes in at least two different varieties (what goes in Seiko 5's is not the same quality of what goes into ISO divers). Hardlex is closer to 7 in the Moh's scale, but is much more flexible than sapphire. IOW's sapphire is harder but more brittle. Hardlex will scratch easier but resists impact much better. You can read more about Hardlex and the different types of it here:

__http://www.larrybiggs.net/scwf/index.php?mod=103&action=0&id=1037842045_

_Sapphlex is also a Seiko proprietary type of hardened mineral crystal that is laminated (layered on the outer side of the crystal) with sapphire. The idea being to provide the best of both sapphires's superior scratch resistance and Hardlex's superior impact resistance.

The types of plastics used to make acrylic crystals has varied widely throughout the years. From a performance POV there are acrylics out there which perform very well in professional divers (most dive computers today use acrylic crystals). The problems with acrylics are that although they can be made to be very very impact and preasure resistant (at least in higher end ones), they are highly susceptible to scratches from simple bumps that would normally not scratch a simple mineral crystal. Provided the scratches are not too deep, they can generally be easily buffed out with the appropriate tools.

Buffing out scratches on mineral crystals (of any kind - sapphire included) is possible, but difficult and time consuming. even then if you are able to remove the scratch, you run the risk of altering the shape of the crystal in that spot. There are no real guaranties as to the quality of results. Although it is possible, it is usually not worth the time and effort to repolish a mineral crystal. Also, since replacements are generally inexpensive, most people prefer to just replace them.

Personally, I have no problem with Seiko's choice of high-end Hardlex (it is not the same stuff that goes on Seiko 5's), as it has superior impact performance to Sapphire and is not that drastically softer than sapphire (7+ on the Mohs scale vs 9 for sapphire).

---------------------------------------

CRYSTAL SHAPES:

The overwhelming majority of mineral crystals (Sapphire, Hardlex, Sapphlex, or glass) come in of of two general shapes: flat or domed. There are tons of variations on the actual shapes of each from (and acrylics come in many more forms). There are pro's and con's to both general shapes.

Flat crystals tend to have a cleaner look and when used in tool watches such as divers, tend to be easier to protect, as they generally sit slightly lower than the bezel that surrounds them. The problems are that the flat shape makes them much more susceptible to impact failure (shattering and cracking), and the shape of the glass tends to act like a mirror when viewed at an angle - especially under water (this issue can be easily resolved with the use of AR coating, IMHO, preferably on the inside of the crystal).

Domed crystals, by their very nature distribute impact forces more evenly around the crystal and are thus more resistant to impact. Generally this characteristics tends to increase with the curvature of the dome. however, because of their raised profile dome crystals are far more susceptible to scratching, especially near the crystal's apex. the domed shape of the crystal naturally does away with the mirroring effect observed in flat crystals, but also distorts the image of the dial underneath it. Again the distortion is more pronounced the greater the curvature of the crystal. AR coating can be applied to domed crystals, but many would argue that it is not really necessary.
_


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## Isthmus (Feb 13, 2006)

Angelis said:


> The most critical info from the second link, IMHO, as quoted from this link: http://www.larrybiggs.net/scwf/index...&id=1176221491


:-d What did you leave out? (LOL) :-d

Thanks for reposting my article here. :-! I could have sworn that I also posted it to WUS when I originally wrote it. I'm pretty sure a copy of it is in the WUS archives either under the seiko forum or the dive watch forum (or both).


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## Angelis (Feb 12, 2006)

I can't help it Isthmus---I saw it and I liked it, and felt that I'd save us all the trouble of searching the archives when we can all enjoy these bits of wisdom. I enjoyed the depth, and found that we both agree on the strong and weak points of both crystals.

However, does anyone still use acrylics? Can they be useful to us in these days?



Angelis


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## Isthmus (Feb 13, 2006)

Angelis said:


> However, does anyone still use acrylics? Can they be useful to us in these days?


Sure the do. As far as I know, there are still dive computers that prefer to use acrylics. If you look further down the page, I think I expanded on the article with a reference to acrylics and the manufacture of sapphire crystals.


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## redryder (Dec 13, 2007)

thanks very much for all the info. Even more than I ever needed to know:-d Not so afraid of Hardlex anymore.


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## aribus (Sep 24, 2006)

Very good info! When I was having my Monster customized, I debated whether to get the Sapphire crystal or not. I decided not to as the Hardlex crystal still looks as good as the day I unboxed it. Good stuff that Hardlex.


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## tundraotto (Oct 29, 2007)

the hardlex is bada$$ - i have managed to get a couple of tiny tiny marks on the monster hardlex - but you cannot see them unless youre looking for them and a sapphire could have broken under the same impacts...perfect for a diver...


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## Angelis (Feb 12, 2006)

I just want to personally thank Isthmus for the info he provided. I think that we can now all bring resolution to the question...


Thanks Isthmus---you are a font of information....:-!


Angelis


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## Harleykat (Oct 9, 2007)

Swatch uses acrylics, you can at least polish many scratches out. My dive instruments do also, but I have plastic covers that adhere to the lens that give extra protection.


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## RogerE (Dec 7, 2007)

To show how good Hardlex is, NASA specifies hardlex crystals for their Astronauts' Omega watches. It is less likely to shatter than is sapphire. Moreover, hardlex is very easily polished to 'good as new' by any competent watchmaker.


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## Angelis (Feb 12, 2006)

That's good info RogerE. I have trusted Hardlex for some time now. The watch industry leans way more toward Sapphire crystal. A good thick curved sapphire crystal is very valuable these days.


Angelis


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## Isthmus (Feb 13, 2006)

Angelis said:


> That's good info RogerE. I have trusted Hardlex for some time now. The watch industry leans way more toward Sapphire crystal. A good thick curved sapphire crystal is very valuable these days.
> 
> Angelis


Sadly that is the watch industry preying on the fashionable but misinformed buying public. Much like how they advertise that watch movements are covered in "rubies" (or jewels). The truth is that there is NO jewelery value to either the rubies or the sapphire crystals, and they are both extremely cheap to manufacture in bulk. Jewlery stores have long sold watches (especially automatics with display backs or skeleton dials) by pushing the "jewels" and sapphire angle, as if it added any additional value to the watch (and often inflate their price accordingly). The uninformed public more concerned with the brand than the watch, simply buys the spiel, hook line and sinker.


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## razcob (Nov 7, 2007)

Isthmus said:


> Sadly that is the watch industry preying on the fashionable but misinformed buying public. Much like how they advertise that watch movements are covered in "rubies" (or jewels). The truth is that there is NO jewelery value to either the rubies or the sapphire crystals, and they are both extremely cheap to manufacture in bulk. Jewlery stores have long sold watches (especially automatics with display backs or skeleton dials) by pushing the "jewels" and sapphire angle, as if it added any additional value to the watch (and often inflate their price accordingly). The uninformed public more concerned with the brand than the watch, simply buys the spiel, hook line and sinker.


If sapphire is not the best, then why does the Seiko MM600 Spring Drive have it. Surely, Seiko could of equipped the MM600 with Hardlex.


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## Fatpants (Sep 6, 2007)

A Sapphire crystal on a watch rated to 600m is between 4 and 6mm thick. Quite substantial and pretty hard to break.


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## Guest (Jan 3, 2008)

razcob said:


> If sapphire is not the best, then why does the Seiko MM600 Spring Drive have it. Surely, Seiko could of equipped the MM600 with Hardlex.


Let's put it this way.

Hardlex is the better compromise on a diver due to its combination of features. For one, it is less brittle than sapphire. One can of course engineer thicker sapphire crystals to compensate, but this comes at the expense of cost and case thickness, among other considerations.

Depending on the env. and usage, I will hesitate to call sapphire 'better' overall.

If one purchases a watch as jewelry or daily wear (e.g. desk diving), sapphire is obviously the better candidate.

To think about: Scratch-free crystal, yes. But what about the bezel? Esp. on divers.


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## Isthmus (Feb 13, 2006)

razcob said:


> If sapphire is not the best, then why does the Seiko MM600 Spring Drive have it. Surely, Seiko could of equipped the MM600 with Hardlex.


I don't know, perhaps because they are trying to move the brand up-market and appeal to the misinformed public who pays extra for sapphire? This btw is the same public who demands that professional diving watches have bracelets with screwed pins, instead of the pins and collars which offer superior performance. Are you going to try and tell me that screwed pins are also the best?

At no point did I say that Hardlex was superior to Sapphire or the Sapphire was "the best" (If you are going to refer to what I've said, please do so correctly). What I did say was that they had different characteristics (Hardlex outperforms sapphire in some ways, and sapphire outperforms hardlex in others), and that the choice of Hardlex over sapphire, because of it's greater impact resistance, was intentional. Don't take my word for it though. Look at Seiko's other high end divers, the MM and all the shrouded divers (including the vintage one rated to 1000m - the modern one uses sapphire) both current and vintage, and tell me what type of crystals they use. AFAIK, they ALL use high performance Hardlex. Do you think that was by accident?

If I've misstated any reference please feel free to correct me.


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## duofold (Jul 12, 2006)

Isthmus said:


> I don't know, perhaps because they are trying to move the brand up-market and appeal to the misinformed public who pays extra for sapphire? This btw is the same public who demands that professional diving watches have bracelets with screwed pins, instead of the pins and collars which offer superior performance. Are you going to try and tell me that screwed pins are also the best?


The SBDB001, while using sapphire for its crystal, uses pins & collars for its bracelet. So it's a compromise watch. ;-) (Isthmus, know that you did not refer your comment to the 600m SD's bracelet...but could you elaborate on the superiority of pins & collars over scews? I had a bear of a time adjusting the bracelet of the watch and wondered about its inclusion.)

Anyway, what seems likely is that Hardlex is yet another triumph of innovation by Seiko and that its implementation in any watch shouldn't be counted as a handicap.


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## Isthmus (Feb 13, 2006)

duofold said:


> ...could you elaborate on the superiority of pins & collars over scews? I had a bear of a time adjusting the bracelet of the watch and wondered about its inclusion.)


Sure. In a pin and collar set up (if adjusted properly), the collar acts like a wedge, effectively locking the pin into place. Once in place (again if it was done correctly), there is little chance of the pin coming loose other than perhaps if it snaps. They are a pain in the ass to adjust, but they sure lock in tightly and securely.

Split pins (the most common set up) are also very effective, but there what is keeping the pin in place is tension cause by the split end of the pin. over time (or if a particular pin is adjusted too many times) that tension is often lost, so they do occasionally fail. They are very easy to replace, with the appropriate tools and they are very inexpensive.

Screw pins are the easiest to adjust. pretty much any tom dick and harry with a small enough screwdriver can do the adjustment in the comfort of his own living room (which is a large reason of why they are so popular). There are two common issues with screwed pins. One is thread stripping. Not form screwing in incorrectly but rather from over tightening. The issue that often shows up with these things is that as with any screw they can come loose over time. People often coat the threads with compounds such as loc-tite in order to prevent this. IMHO, this should not be necessary if the design was sound 100%. I'm not saying that it isn't, but rather that with screws you trade ultimate security of the connection for ease of adjustment.


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## Trea (Oct 30, 2007)

I'm not sure about Hardlex, but I have an old Seiko Windward that has a Saphlex crystal. It was my daily beater for many years and while the watch itself is pretty beat up, the crystal doesn't have a single scratch on it.


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## Guest (Jan 3, 2008)

Isthmus said:


> Split pins (the most common set up) are also very effective, but there what is keeping the pin in place is tension cause by the split end of the pin. over time (or if a particular pin is adjusted too many times) that tension is often lost, so they do occasionally fail. They are very easy to replace, with the appropriate tools and they are very inexpensive.


You may also find that the link holes go off-round due to the effective 2-point bulge of the split end.

This also means there is an effective gap between link and pin along the rest of the pin (it is effortless to insert/remove a split pin before the bulge). Water and debris (like soap suds) can get in and cause corrosion or abrasion.


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## Isthmus (Feb 13, 2006)

Trea said:


> I'm not sure about Hardlex, but I have an old Seiko Windward that has a Saphlex crystal. It was my daily beater for many years and while the watch itself is pretty beat up, the crystal doesn't have a single scratch on it.


Read what my article says about sapphlex and it's characteristics. I'm actually surprised that more high end seiko's don't use it. I heard somewhere that seiko was dropping sapphlex production, but I don't know if that is true or not. IMHO, this company could go a long way toward educating consumers about the pros and cons of each material, and thus making a case for it's choices, as opposed to simply going with what the market erroneously perceives as being superior in every way.


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## duofold (Jul 12, 2006)

Very nice, Isthmus...makes perfect sense.

Yes, I was worried about performing the adjustment properly. However, in the nearly 11 months since adjustment, the pins appear to not have moved even a nano.

For those attempting to adjust pin & collar bracelet for the 1st time as I did, do it over a piece of white cloth. Terribly easy to lose those collars. I spent a while searching for a needle in a haystack (or in this case, a collar in shag carpet).


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## Isthmus (Feb 13, 2006)

duofold said:


> For those attempting to adjust pin & collar bracelet for the 1st time as I did, do it over a piece of white cloth. Terribly easy to lose those collars. I spent a while searching for a needle in a haystack (or in this case, a collar in shag carpet).


Also, keeping a good magnet handy (but away from your watch, of course) really helps in finding those loose collars, or the occasional flying spring bar.


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## Nick1016 (Aug 29, 2007)

Isthmus said:


> Also, keeping a good magnet handy (but away from your watch, of course) really helps in finding those loose collars, or the occasional flying spring bar.


This is a great idea--thanks Isthmus. I might have to go out today and pickup a magnet so that I can go hunting for that Monster bracelet collar that I know is hiding in my basement...


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## Trea (Oct 30, 2007)

Although I am not familiar with all of the current Seiko models, I haven't noticed any that were using the Sapphlex crystals. I don't have a newer Seiko yet (have one on the way) so I don't have any experience with the Hardlex crystals. But if you saw the condition of the bracelet and bezel on my watch versus the condition of the crystal, you couldn't help but be impressed with the Sapphlex. That was a great article btw, very informative and interesting.


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## Isthmus (Feb 13, 2006)

True. Sapphlex is a very nice technology. I wonder whether seiko discontinued using it.


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## vokotin (Jun 2, 2011)

OOOPS sorry for the bump guys my fault, I posted in the wrong thread.


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## fastward (Aug 6, 2010)

vokotin said:


> OOOPS sorry for the bump guys my fault, I posted in the wrong thread.


Noob.;-)


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