The home key is a sapphire crystal. Sapphire crystals are highly resistant to scratches, chips, and cracks. The back cover is encased by hand with luxurious Scottish leather. This fine leather is meticulously crafted to exacting technical and quality standards for everyday handling. The plating on the phone's front frame and camera bezel is 18 carat gold. The marking inside the phone above the battery compartment authenticates that the product contains 18 carat gold.