Apple's official cases for the iPhone 6 come in a leather option and a silicone option. Both offer a colour-matched microfibre interior, slim build and cut out sections to give you easy access to all the necessary controls.
Apple say that "Made from premium, hand-selected leather treated with high-quality aniline dye, each leather case looks and feels luxurious. The leather fits perfectly over the curved form of iPhone 6 and iPhone 6 Plus with a colour-matched microfibre interior to keep your phone — and its camera — beautifully protected. All without adding bulk."