Old 'Barber hone' grits'

[kelbro]

There are a lot of 'barber hones' on the evil auction site. Many are brown, some red, some dark grey/black, etc...

How would you go about determining what grit the stone would be classified as? Comparing scratch patterns to the one created by a 'known' hone?

Some of them go cheap enough to just give them a try and see how they shave but what was the criteria for calling a hone a 'barber hone'? I'm guessing that many of them are hard arkansas stones of one sort or another.