Sapphire crystal is a kind of crystal synthesized by artificial compression. It has the advantage of high density and is not easy to appear scratches. The hardness of the sapphire glass is second only to the hardness of diamond, with a hardness of 2200-2300 Vickers (seven times that of steel) and a Mohs hardness of 9. It has good hardness, good luminous flux, low friction, high temperature resistance, and is better than crystal glass mirrors and synthetic glass mirrors have higher abrasion resistance. But it also has shortcomings, that is, it is not shockproof, and it is not suitable for inappropriate operations such as bumping, heavy pressure, and heavy falling. The sapphire crystal is prone to cracks when your watch is dropped or struck.
Sapphire crystal composition
The sapphire crystal installed on the watch now is actually aluminum oxide with impurities such as iron oxide and titanium oxide removed. Chemically speaking, there is no difference between synthetic sapphire and natural crystal. Because no other elements are added, it is colorless and transparent and has no “blue” color. The original synthetic sapphire is made from pure aluminium oxide at high temperatures, cut into discs by diamond tools, and then polished into the crystal. The cost of processing tools is high, which is one of the reasons for the high cost of sapphire crystals. The technology of synthetic sapphire was invented in the 19th century and has been used in watches since the 1960s, and now top watch brands generally use sapphire crystals.
Advantages of sapphire crystal
Sapphire is very hard, it will not be scratched, it is an inevitable choice for top watches. Whether it is natural sapphire or synthetic sapphire, it is one of the hardest substances on earth, with a hardness of 9 on the Mohs scale. In nature, there is nothing harder than diamonds. Note that what we say here is not in nature, not in the earth. Some man-made silicon carbides can also be grade 9 in hardness and can also scratch sapphire. Many construction and decoration materials also use silicon carbide, such as artificial stone, etc., so if friction occurs in these places, it is possible to leave scratches on the sapphire crystal.
Disadvantages of sapphire crystal
Like glass, it is brittle and easily broken. Therefore, once the sapphire crystal is broken, the resulting repair costs will be very expensive, because the watchmaker must carefully check to ensure that no sapphire debris is left in the movement before replacing the crystal. Other than that, it’s a powerful fingerprint collector, so it needs to be wiped frequently for a shiny, scratch-free finish.
Sapphire mirror maintenance
The sapphire crystal does not require much maintenance, just wipe it with a soft cloth if you are not used to fingerprints. But watch out for grime!
How to Identify Sapphire Mirrors
1. Breathing method
Take a breath on the surface, and the mist that quickly disperses is the sapphire crystal glass. Generally, the moment you take your mouth away from the top of the crystal, it disperses, and you can no longer see the mist when you look at the surface.
2. Tap method
Gently tap the surface with your fingernail, remember, it must be light, the fake is likely to be knocked out, and it will be bad to ask you to pay for it. If the sound is dull, it is the sapphire crystal surface. crystal or glass, the sound is clearer.
3. Drip method
Under the conditions, drop a drop of water on the surface, and then stand up the surface, the water drop will not spread, and slowly slide down, it must be slowly, very slowly, very slowly, this is sapphire crystal.
4. Touch method
It can be touched with the skin of the face, and when touching the sapphire glass, there will be a cool feeling, which is not found in other glasses.
5. Look at the logo of the watch and the hardness of the glass:
If it is a regular brand watch, sapphire glass is generally printed on the back cover of the watch. It is expressed in English SAPPHIRE or Sapphire Crystal. Now even fake or counterfeit watches use sapphire glass. To test the hardness of the watch glass, you can use a sharp metal object to scratch the most inappropriate part of the edge of the watch glass. It feels very hard, and there is a feeling of metal objects drifting by. If the glass is not scratched, it should be sapphire glass.
Can the synthetic glass crystal be replaced by a sapphire crystal?
No, because the thickness of the case is not the same. Typically, sapphire mirrors are thicker than synthetic glass mirrors. You might be able to find a sapphire crystal in the right size, but that would also destroy the water resistance of the watch. In addition, as a result of this, many manufacturers will refuse to provide maintenance and repairs for your watch.