We believe that quality matters. So we made the decision early on to only use the highest quality sapphire crystal glass for our watches, rather than cheaper, lower quality, mineral glass.
The clear surface that covers the face of a watch and protects it is called a crystal which can be made of an array of materials. The three most common are Sapphire crystals, Mineral, crystals, and Plexiglas or Hesalite crystals. Plexiglas is referred to as plastic and Hesalite is an acrylic crystal.
The crystal cover on a watch usually depends on the price of the watch or whether it has been designed to withstand rugged conditions. The different crystals will dictate the price of the watch, meaning a Sapphire crystal will be more expensive than a Plexiglas cover.
Sapphire Crystal (What we use):
High-end expensive watches usually have Sapphire crystals and for a good reason. Sapphire is very strong and scratch resistant and is a more expensive crystal than the others. The advantages to a Sapphire crystal include its resistance to scratches, shattering, it can withstand cracks and a lower chance of breaking.
Mineral crystals are actually a common glass crystal that has been treated with heat or chemicals to prevent scratches. Although it is not as resistant to scratches as sapphire, it is much better than plastic. The downside, if you are in extreme heat or cold and your watch hits against something it can crack or even shatter.
Sapphire vs Mineral:
If water gets on a sapphire crystal, it will come together forming a bead. If water gets on a mineral crystal, the water will separate in different directions.
A sapphire crystal can appear as a slightly tinted pink or milk white color, while mineral is often blue.
Sapphire crystal is cold or icy to the touch where the mineral crystal is not.
If you need more information about the crystal on your watch, there are machines that can measure the density, luminosity, hardness, and the index of refraction.