Cliff

DMT has a chart for their diamond stones:

https://www.dmtsharp.com/sharpeners/bench-stones/duosharp/

you need to click on the [View DMT Grit Chart] button to see it. It says

120 micron = 120 mesh = silver
60 micron = 220 mesh = black
45 micron = 325 mesh = blue
25 micron = 600 mesh = red
9 micron = 1200 mesh = green

Each stone has a colored dot on it, and the colors are just a
nomenclature for DMT.

I have the last four diamond stones on the above list. When sharping a
tool found out in the wild, I typically start with the black stone to
flatten the blade as quick as possible, skip the blue, because
honestly it doesn't see to be much different than by black (or perhaps
the black stone is worn out). Then I go to red, green, a 1000 grit
water stone, 4000 grit, then 8000 grit. So in other words, if you want
to deal with powder, 60, 25, and 9 micron.

If I remember correctly Leonard Lee wrote a book called the "The
Complete Guide to Sharpening" with a chart that converted microns to
grit size.

Thank you,
Chris