Gold and sapphire. No, we're not talking about Rolex wristwatches but the iPhone 5S. All rumors of course.

The iPhone 5 already has a sapphire lens cover. But the 5S will get a convex sapphire home button too, according to KGI Securities' Ming-Chi Kuo (via 9to5Mac).

The reason? Sapphire prevents the button from being scratched and a slightly convex shape creates room for the fingerprint sensor, according to the analyst.

Note that there has also been speculation that the 5S' touch display would handle fingerprint sensing chores.

A fingerprint reader could pave the way for more secure mobile payments or be used as a more secure way to access a user's Apple account.

The "champagne gold" colored iPhone 5S seems a bit wacky. But the Japanese site Macotakara reiterated Sunday (a rumor it's reported before) that this color may be available for the 5S.

The KGI analyst also mentioned the new iPhone 5S will keep the 8-megapixel sensor but make other camera improvements.

Another notable iPhone 5S rumor has it sporting a new Apple A7 processor.

Apple may introduce new iPhones on September 10.