WATCH TALK FORUMS banner
1 - 14 of 14 Posts

·
Registered
Joined
·
1,573 Posts
I may be wrong, but I don't think so. You could certainly tell the difference between sapphire and plastic, but I'm not sure you tell good quality mineral from sapphire without a way to test the hardness/scratch resistance.
 

·
Registered
Joined
·
1,101 Posts
Which - sapphire?
thats correct, sorry, shoulda been more specific.......
If you drip a drop of water onto a watch crystal you can tell if it is Mineral or Sapphire, most of the time.

The bottom edge of the water drop (where it touches the crystal) will be FLAT on mineral, will be ROUNDED on Sapphire.

Water beads on Sapphire.
 

·
Registered
Joined
·
1,573 Posts
Good to know! I'm always learning new stuff around here.
 

·
Registered
Joined
·
2,069 Posts
... And what would those advantages be for mineral?

Not hard enough to not get scratched, but too hard to polish scratches out. Less impact resistant than either plexi or sapphire. Cheaper? Plenty of affordable watches with sapphire... Sorry, just don't see where mineral fits in today's world.
 

·
Registered
Joined
·
1,101 Posts
... And what would those advantages be for mineral?

Not hard enough to not get scratched, but too hard to polish scratches out. Less impact resistant than either plexi or sapphire. Cheaper? Plenty of affordable watches with sapphire... Sorry, just don't see where mineral fits in today's world.
An acrylic watch crystal is a kind of plastic, which has the advantage of being resistant to shattering, but can be scratched easily. Fortunately, scratches can be easily removed from acrylic. Mineral crystal is a kind of glass, which is more scratch resistant than acrylic, but not as as good as sapphire. Mineral crystals are also somewhat better at shatter resistance compared with sapphire. Unlike acrylic, scratches in mineral glass are more difficult to buff out; and unlike sapphire, mineral glass will scratch. In my opinion, the mineral crystal seems to be a poor compromise between the two extremes. A sapphire crystal is indeed made of synthetic sapphire, which is a transparent form of corundum, or aluminum oxide (Al2O3). It is extremely hard (Moh's scale 9), and will resist scratching by most substances short of diamonds. However, if struck sharply and from the correct direction, sapphire will shatter easier than mineral.
With all this said I somewhat agree with you and prefer sapphire in my watches if available.:001_smile:
 

·
Banned
Joined
·
28,291 Posts
Then my next question is, how is Sapphire coated done?
Just like the lenses in eye glasses - it's anti-reflective coating. That's what scratches on sapphire most times, and why many watch companies coat the inside of the crystal nowadays.

.... or are you talking about the sapphlex / "flame fusion" crystals which have a layer of sapphire over glass? I can't see the point of them beyond strange marketing claims. If that's what you're asking about, the top layer is deposited using PVD or CVD.
 
1 - 14 of 14 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top