Apple Watch has 3 collections: Apple Watch, Apple Watch Sport and Apple Watch Edition. Apple Watch and Apple Watch Edition have glass display made from Sapphire glass.
The Apple Watch Sport collection is using Strengthened Ion-X glass to get a light glass display and fit for your sport activities as it is written on Apple’s official website:
“To keep the Sport collection models as light as possible, we used an aluminosilicate glass that’s especially resistant to scratches and impact. It’s fortified at the molecular level through ion exchange, with smaller ions being replaced by larger ones to create a surface layer far tougher than ordinary glass”.
Apple explained the Ion-X glass technology:
“Ion-X glass is the same material used in the windows of space shuttles and high-speed trains. This glass is thin and light, yet surprisingly strong — five times stronger than regular glass. There are many ways to strengthen glass at the surface, but Ion-X glass is hardened down to its molecules. During the manufacturing process, the glass is dipped in a 750-degree molten potassium salt bath. That’s when ion exchange takes place, with the smaller sodium ions being removed from the glass and replaced by larger potassium ions. As the glass cools, these larger ions create an extremely hard surface layer that is resistant to scratches and impact.”
But what about the strength of Ion-X of Apple Watch Sport collection?
We can watch its scratch test video:
It’s seen that Ion-X glass is resistant to scratch from common, but it is not resistant to sand paper and like the previous prediction the display glass of Apple Watch Sport is as strong as the iPhone’s. Of course, Ion-X glass is not as strong as Sapphire glass display on Apple Watch and Apple Watch collections.