Chinese smartphone maker Xiaomi Inc has tapped South Korean manufacturers to produce sapphire covers for a limited edition premium smartphone that it may launch as early as the year-end, South Koreas Electronic Times reported on Friday. The report, citing no sources, said Xiaomi had ordered sapphire covers for 50,000 smartphones. Xiaomi declined to comment. Industry giant Apple Inc is considering using sapphire screens in more expensive models of its new, larger iPhones if it can get enough of the material, the Wall Street Journal reported earlier this month, citing unnamed sources.