Could sapphire screens make smartphones crack-proof? Here's an idea with some real value. Smartphones of the future might be coated in industrial sapphire instead of glass -- it's made from corundum, one of the hardest natural minerals in the world, second only to diamonds. The lab-grown substance, made by GT Advanced Technologies, is a natural for today's smartphones given its scratch-proof properties. The company claims GT ASF Grown Sapphire is about two and a half times the strength and scratch resistance of the popular Gorilla Glass, which is currently used to protect iPhones and other high-tech smartphones. It's virtually scratch-free," said Jeff Nestel-Patt, marketing director for the company. And screens wearing these gems may come as early as this year, said Eric Virey, an analyst for market research firm Yole Developpement "I'm convinced that some will start testing the water and release some high-end smartphones using sapphire in 2013," Virey said. Nearly unbreakable smartphone screens would be a welcome change for anyone who's ever dropped a new Android-powered gizmo or iPhone only to watch their expensive gadget crack or shatter. But let the buyer beware: Sapphire-fronted smartphones are likely to be even more expensive. Gorilla Glass screens cost less than $3, according to Technology Review, while a sapphire display could about $30. Expensive, yes. But that's an asset you can hold in your hand.