I've been talking about chocolate gold for a year now -- seeing it in more European lines like the luscious Mattioli brand from Italy (gorgeous designs!!!). And of course, designers are asking where can they get it.
So I made a few calls to United Precious Metals & David H. Fell (where you can buy all colors of gold) and to the U.S. office of Mattioli and confirmed that it is NOT an alloy but a surface treatment. It's a very high tech metallurgic magic (PVD or physical vapor deposition) that turns titanium a rich chocolate color (actually can turn it lots of different colors) that is added to a gold design.
In a related color story we saw bronze alloys in play this past fine jewelry market. Similar warm tones but way cheaper material. Think fine jewelers will go for this?