You seem to have the tags confused.The first number is the foreground color. The second number is the background color. The third number is the color intensity.Theoretically, there are 4 shades of greyscale available. Black, Dark Grey, Light Grey, and White.As I pointed out, I dug through the raws for stone mineral (Not the layer stone color value, which lists wall colors and the like.) and gems do not list any (normal) candidates for dark grey. I am fairly certain that all gems have the intensity value set at 1.Black would have color value 0:0:0You really do need dark grey if you want to have greyscale images. Black just wont look right.