I am pretty sure that is a Mojave Yellowbelly. The color is a little darker than a standard Mojave, the blushings go up the sides very nicely, and the alien heads are more granite like than a standard Mojave. All those features lead me to believe that you have yourself a Mojave Yellowbelly.

Here is a picture of a Mojave next to a Mojave Orangebelly (Orangebelly is a high quality line of Yellowbelly that sometimes produces Graphite Ivories). These are from the same clutch, with the Orangebelly Mojave on top and the Mojave on the bottom. The Orangebelly Mojave has a slightly different background color than most Mojave Yellowebellies that I have seen, but you can see the high blushings and the granite like alien heads in this picture.