Glass is used to describe the transparent cover of the watch, which can also be referred to as crystal. Glass is used to protect the dial but can also be used on the reverse of the watch to make a transparent open caseback, which shows the inner workings of the watch mechanism.
Sapphire Crystal Glass
Sapphire crystal glass is commonly used because it is highly scratch resistant and extremely hard wearing. It is completely transparent, enabling you to see every intricate detail on the watch dial and is one of the hardest natural substances making it an excellent protector.
Mineral glass is often used as an alternative to sapphire crystal. Lower priced watches can feature mineral glass, but also some older Rolex models may also use this type of glass.
Plexiglas is the trade name for an acrylic glass, often used as a lightweight or shatter-resistant alternative to glass.
The origin of a watch is where it has been assembled. Many watch brands are Swiss-made but there are a number of brands that originate from other countries, for example U-Boat is made in Italy and Bremont is made in England. Some watch brands will use Swiss-made parts, such as the movement, but the watch will be assembled elsewhere.