Russia's Monocrystal identified as Apple Watch sapphire supplier

The company's annual revenue is up to $87 million, and it was one of the only sapphire manufacturers to post an operating profit by the end of 2014, according to Sputnik News. The depreciation of the ruble in the past year — owing to falling oil prices, and economic sanctions after the invasion of Ukraine — has made it more economically competitive.

Apple uses Monocrystal's 2-inch sapphire wafers, which account for 40 percent of the latter's output, Sputnik said. Monocrystal is reportedly looking to exploit the low ruble to boost 2-inch production from 4 million units a month to 5 million by the end of the year.

It's not clear how much of Monocrystal's wafer production might be dedicated to Apple, as it serves a number of clients, including other watchmakers.

Apple has also been vague about the number of Watch sales so far, claiming success but choosing not to publish any unit numbers or even break out revenue. Analyst estimates have varied wildly for the June quarter, anywhere between 2 million and 4.2 million.

The company's original sapphire supplier was supposed to be an American firm, GT Advanced Technologies, with which it helped establish a factory in Mesa, Arizona. GT ultimately went bankrupt however, blaming unreasonable demands by Apple, something the latter denied. The aftermath is still being resolved in court.