Apple apparently isn't satisfied with sapphire screens for its new iPhone 6 and iWatch. Despite being the second strongest material on the planet it appears to have developed a method to make it even stronger.

Apple's patent for a method of strengthening sapphire glass has appeared online ahead of its expected iPhone 6 and iWatch unveil this Tuesday 9 September. Rumours are still unclear on weather sapphire glass will feature in the devices.

This patent suggests that Apple has taken its myriad cracked iPhones around the world seriously and wants to make a near unbreakable screen.

The method described involves "ion implantation" to add another layer in the crystalline structure of sapphire so as to further enhance stability. This would also allow Apple to create the darker bezel areas in the glass itself by using iron or titanium ions to tint and strengthen the glass. For the main screen other materials can be used to ensure it remains translucent.

There are plenty of ways to impregnate a screen with ions. How Apple will do it, or has done it, is not yet known. We'd expect this super strength sapphire glass in the iWatch at least, if not in the larger 4.7-inch iPhone 6 or 5.5-inch iPhone Air.

Check back on Tuesday 9 September for live coverage of the Apple launch event.

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