Till now, we knew that Apple will give its iPhone 6S and iPhone 6S Plus Rose Gold color but now as per reports Black Gold plating might also be available for these handsets soon. A Vietnamese company Karalux is offering Black gold plating service for the new iPhone 6S in addition to its more orthodox 24K gold plating jobs.
According to the source, the color is created by mixing gold with the rhodium in a specific ratio. The technical director of this Vietnam company says that rhodium itself is about 6 times more expensive than gold. It takes 8 hours to cover an iPhone with the black gold coating, so we can assume the phone is not cheap at all.