Sapphire has been used for watch crystals (and increasingly for case backs) for quite a while now. My "precious" digital camera has a sapphire cover on the LCD

Sapphire has been used for watch crystals (and increasingly for case backs) for quite a while now. My "precious" digital camera has a sapphire cover on the LCD. It's interesting what they're doing in terms of shapes beyond sheets and simple "lens" type constructions. I made a foolish watch purchase because the sapphire case back was especially compelling. (This isn't my video, but it's the same watch: http://www.youtube.com/watch?v=DxNgAXDDTgo http://www.youtube.com/watch?v=DxNgAXDDTgo) I've wanted a camera lens made of sapphire front and rear elements, but the refraction index would require more custom engineering than it would be worth. Definitely more expensive than a few $10 UV filters. :-)