STERNGLAS uses sapphire crystal because it's particularly scratch-resistant and suitable for everyday use.
Compared to many other watch glasses, sapphire crystal is significantly more resistant to typical signs of wear. This helps the glass stay looking clear and high-quality for a long time, even with regular wear.
A watch is constantly coming into contact with clothing, desks, bags or other surfaces in everyday life. Sapphire crystal reliably protects the dial and is very durable.
Please note, however: even sapphire crystal isn't indestructible. Hard knocks, falls or contact with very hard materials can cause damage.