EDITOR-IN-CHIEF
Gary George Girdvainis gary @ isochronmedia . com
Is Sapphire King ?
If you think about it , there are effectively four types of watch crystals ; sapphire , mineral , acrylic / polycarbonate and , to a lesser extent , various versions of Corning ’ s Gorilla Glass . There are also coatings for both scratch resistance and light refraction , but that ’ s a different topic . Focus on the current dogma that dictates sapphire is king and THE preferred material for better watches . After all , it ’ s almost scratch proof , so how can anything else compare ? While I do appreciate the nearly scratch-proof nature of sapphire crystals , I ’ ve also experienced their weaknesses , and I ’ m willing to bet I ’ m not the only one . Whether my catastrophic shattered crystal at the airport X-ray , or the time I smashed it into a door handle at home – sapphire might not take scratches , but it will and does fail completely when subjected to impact . It looked like new - until suddenly it didn ’ t .
Next stop , a somewhat costly repair that may necessitate a full disassembly to remove any shards that may have found their way into the nether regions of your watch . How it shattered is irrelevant , but at that moment of destruction , I ’ m certain most owners would have wished for a tougher option that would have withstood the particular impact .
In my experience , sapphire is best utilized as a flat crystal with its poor optical qualities mitigated by the use of ( internal only ) antireflective coatings . While domed versions are also popular , they do add additional risk for lateral impact but the light reflection may not be as attenuated .
One sapphire shape that I will rail against right here is the “ boxed ” crystals . These rise vertically from the bezel with a small step , and while they revisit a popular shape from vintage watches , the originals were almost always crafted from acrylic ( hesalite ) and were much tougher on impacts than the newer favorite sapphire .
Acrylic crystals do scratch easier , but they are optically superior , mechanically tougher , and relatively easy to buff out – or in the worst-case scenario , inexpensive to replace . If you do find a way to crack an acrylic crystal , they simply don ’ t shatter the same way a sapphire will , and repairs tend to be limited to the cost of the xtal and the basic installation .
In my opinion , mineral crystals are the worst of both worlds . While they are more scratch resistant than Hesalite , they are not nearly as tough . They are harder to break than sapphire , but will take scratches . In my experience mineral crystals in watchmaking should be reserved for exhibition backs only , where the likelihood of scratch or impact are nominal , and reflection of light less important .
Based on what I ’ ve learned , I ’ m almost certain that the Gorilla Glass ( DX + or Victus ) is the very best material that ticks all the boxes . The only problem is that Corning does not make it easy for any watch brand to get the good stuff . Some smaller brands have used older versions of the glass , but the top-of-the-line materials are difficult to acquire ( unless you are Apple , Android , or Nokia ) and – if it matters , they are also fabricated in China .
I know a lot of experts out there may not agree with me , but after three decades of experience , contact with collectors and constant interactions with certified and master watchmakers , my opinion has evolved from a “ Sapphire is King ”, to a more rounded appreciation of what these materials are , and are not .
It ’ s AboutTime – To look through the right glass .
Gary George Girdvainis
4 | AboutTime Magazine