The iPhone 5S rumor mill has so far offered up three possible colours - black, white/silver or gold (also cited as champagne around the web).

Now pictures posted to the web by Sonny Dickson show what appears to be the new device in a grey or graphite color with a black trim.  

There has been huge speculation about the release date of the phone, which may not even be called the iPhone 5S.  

With Apple expected to hold an event unveiling its next generation of phones on September 10, some have anticipated a September release.  

Japan's Nikkei reports sales of the iPhone 5S there from September 20 onwards.  Chinese news site First Finance Daily has put the release date in China at November 28.  

The iPhone 5S is expected to have a fingerprint sensor in the home button that will authenticate the user and make payments with the device much easier.  

There are also rumors of a much speedier A7 chip.  

Clayton Morris of Fox News tweeted: "Sources are telling me the new iPhone's A7 chip is running at about 31% faster than A6. I'm hearing it's very fast."

He was quoted in a report by 9to5Mac stating that Apple has tested 64-bit A7 chips for the iPhone 5S, but dual core like the iPhone 5's A6 chip.  

The same website has reported a new slow-motion camera mode that captures 120 frames-per-second video, rather than 30-frames-per-second.  

Morris also tweeted: "I've also heard there's a separate chip devoted to motion tracking.  Should be an interesting camera upgrade." 

The device is expected to release around the same time as the rumored lower cost option, iPhone C, with leaked photos for that model showing a much brighter range of colours.