BBW/Codicule Slurry or not?

[Highwayman]

I bought a box of odds and ends at an estate sale that turned out to be a treasure chest. It was supposed to have contained an assrtment of tools(it did) but at the very bottom of this $10.00 box was gold mates. There were two vintage wedges (no scales) which I posted yesterday in the workshop forum, but also an Escher hone and a BBW /Codicule natural hone both with no chips or dings. My questions are about the BBW/Codicule ( at least thats what I think it is). Pix are terrible sorry. I aways heard the BBW/side was blue . This appears to be more of a brownish color with the same color slurry when lapped on a DMT. I do not have slurry stones for either side but I have heard there are those who use only water to preserve the hone. Also what is the use of the BBW side. I know the Coicule side is supposed to be a superb finisher. ( I have only honed with synthetics so I have no experience with naturals.) Hope some experienced honers will give shed some light.