The Sapphire glass used in most models of Apple Watch is more durable than the Ion-X glass Apple used in the Apple Watch Sport, but its image quality in ambient light conditions are not as good. According to a report by Apple Insider, Sapphire displays have a screen reflectance of about 74 percent more than Ion-X screens which affects color gamut and contrast. In total darkness, the performance was the same; however, but in broad daylight, the quality of the display on Sapphire glass fell sharply compared to the other material.
The least expensive Apple Watches (with Ion-X) start at $349, but the “cheapest” Sapphire model is $549.
