Many genuine watches use a crystal (the glass face of the watch) made from a large piece of synthetic sapphire. Sapphire is highly resistant to scratches and chips. It's a perfect material for watch crystals and see-through case backs. Sapphire crystals are nearly transparent at any angle. They have very little distortion unless their thickness is greater than average (like on a Panerai PAM-127 1950 replica).

Sowing the Seeds of Misinformation

The replica watch industry is driven by a lot of misinformation.  Many of the large commercial web sites try to entice you into spending hundreds (if not thousands) of dollars on a piece of counterfeit goods.  They try to make this purchase attractive by convincing you that the watch is of the highest quality; "99% accurate."  In reality this is not the case.

There is a huge marketing effort put forth by a variety of replica watch dealers on the Internet. This effort is geared towards providing misinformation in order to give a sense of authority and exclusivity. In reality it's all related to selling snake oil...

For years ETA, the leading manufacturer of Swiss watch movements, has been selling their stock to OEM vendors. These high quality movements have found their way into most of the "Swiss" replicas on the market. The vast majority of these movements have 25 jewels in their design.

One of the easiest ways of spotting certain fake Panerais was to flip the watch over and look at the movement through the exhibition case back. The counterfeit models used a non-modified Unitas 6497 movement, while Panerai used a heavily revised version that included a signature "Swan Neck" bridge. If your watch didn't have the swan-neck bridge it was probably fake.

Recently several Unitas movements used in replica watches have been sporting a version of the swan-neck bridge. Ziggy gives his breakdown of this modification. A fascinating read if you're a Panerai fan.

I saw this posted on The Replica Collector today, which is a detailed FAQ on watch crystals.  It's a good read for people who don't know about the different materials used in watch crystals.

WATCH CRYSTAL Q & A

What is a watch crystal?

What are watch crystals made of?

What are the advantages and disadvantages of each material?

What exactly is synthetic sapphire?

Can you tell if a crystal is made of sapphire by looking at it?

Are scratch-resistant crystals new?

Are all scratch-resistant crystals made of synthetic sapphire?

The terms "lunette," "bombé", "chevé" and "boule" are sometimes used to describe watch crystals. What do they mean?

What are "anti-reflective" or "glare-resistant" crystals?

How much do watch crystals cost to replace?