Spinetti's sells a diamond mold chip on its website -- 11.5 grams for 6 cents each.
They only have 3 colors (red, white, blue), but could be available elsewhere in other colors.

http://www.spinettisgaming.com/11.5gram-Heavy-Diamond-Chip/

Both chips (Banana Room and Spinetti's) have 26 diamond pattern and look very similar.
For side-by-side comparison, here's images of each: