Coloured equation in Impress

There is a color statement in Math that can be combined with a limited palette (RGB+CMYK+white) to set the hue of elements.
 
The basic form is:
 
color <keyword> { math element }
 
Valid <keyword> entries appear to be: red, green, blue, cyan, magenta, yellow, black, white. For example:
 
color red {sum from{color magenta {i=1}} to{color cyan{100}} color blue {i.}}