Sapphire just was used to make high-end luxury watch in the past. It has a very high price. If it is used to make irregular face of watch, such as arch, spherical, polygonal and so on, the producing process will be more difficult. But in modern society, sapphire crystal watches are quite common, it is largely used to make watches. Nearly every person can have a sapphire crystal watch.

As we all known, the greatest advantage of the sapphire glass is that sapphire is very hard, wear-resistant, which is quite important for maintaining a luxury watch well for a long time. So, if one watch uses sapphire, there will be English label “Sapphire” on the face or the back of a watch.

Sapphire crystal glass is very helpful to enhance the waterproof performance of watch, especially for diving watch. For example, in order to keep a watch well in 300 meters deep, the thickness of the sapphire should be 3mm or 4mm to withstand tremendous pressure in deep sea.

Of course, there are many fake watches without sapphire face. So how to identify the true sapphire becomes a question.

Laboratory Test

Detection of watch’s sapphire is very similar to the identification of jewelry. The used equipments are the same. Expert usually uses a refractometer to identify jewelry. It can tests the refractive index of productions.

Although all sapphire glass is artificial, its refractive index is the same as natural sapphire. They are both 1.76 ~ 1.77. Because sapphire is crystalline solid, it has re-refraction which is 0.008 as crystal.

It is easy to observe plane face. If the face is spherical, it needs paint refractive oil while testing. The refractive index mineral glass is about 1.52. We can easily distinguish it and sapphire. Moreover, it has no re-refraction.

Another method is to use polariscope. All crystalline solid can be detected using polariscope like crystal. While detecting sapphire, rotating the polariscope, we can see alternate-changed bright and dark light. Turning 90 degrees the light change one time. When detecting watch’s glass use polariscope, the movement should be removed.

Drop water on watch face

Dropping a drip of water on watch’s face, if the drip represents spheral, the faced is sapphire. However, if the drip spreads out, it turns out the face is not sapphire. As for the scientific reason, I really have no idea. I think it is because sapphire has large density. It is just my guess.

Watch watch’s label and the hardness of glass

Generally speaking, standard watch manufacturer will label “Sapphire” or “Sapphire Crystal” on the back. Using a sharp metal piece to carve the most inconspicuous edge of face, if the glass is not scratched, the face is sapphire.

Article Post by Swiss Replica Watches Store