Sapphire Crystal | GRHardnessTester.comSapphire crystal could soon be the new screen of cell phones because of its hardness and scratch resistance.  Currently, it is used for bullet proof glass, high pressure science equipment, high-end watch faces, and more.  It is more advantageous for phone screens than normal glass because of its scratch resistant quality.  According to Mohs hardness scale, normal glass has a hardness value of about 5.5 to 7 while Sapphire crystal has a hardness quality of 9.  Diamond ranks the highest on Mohs scale of hardness with a hardness value of 10 so Sapphire crystal is only slightly less hard than diamond.  The current material used for phone screens is Gorilla Glass.  Although Gorilla Glass has not yet been rated on Mohs hardness scale, it is expected to have a hardness value of about 7.  Any material that ranks higher on Mohs scale can scratch a material that ranks lower.  With sapphire screens having a hardness of 9, almost anything that is carried in a pocket will not be able to scratch them.

So, what’s holding back companies from switching to sapphire screens?  Well, a big reason is cost of sapphire crystal.  According to Corning, a sapphire screen would cost about 10 times more than a Gorilla Glass screen.


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