Hex #99b091 or rgb(153,176,145) in RGB space is the tint of grass green. It has hue angle of 104.52 degrees, value = 69 and saturation = 18. #99b091 can be obtained by mixing 3 colors: 3 drops of yellow, 4 drops of blue, 3 drops of white.
Nearest safe hex - #999999. Below you can see the block with #99b091 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #99b091 to the mixer and play with it.