A Keen Kutter Konundrum

Long story short. Keen Kutter barber hone arrived today, greenish gray color on the fine side, black on the reverse. Excellent condition, just needs a lap. Start lapping, fine side turns gray. Binder is fine, the stone is hard as hell, took it up to 2000 wet dry, surface is glassy smooth.

Now I've seen other pics of this hone before and the fine side definitely has a green hue, see here: https://www.tomonagura.com/Natural-R...en-kutter.html

This has me wondering whether at the factory these were rubbed with CrOx, or even buffed with CrOx on the fine side to enhance the polish/keenness of the stone. Should I do the same if this is the most plausible explanation?

Some of the green was left in the logo area and I could scrape it from the surface with my fingernail. Seemed waxy.

If anyone can chime in with info about this hone or any other theories it will be very much appreciated.

Pics of hone, color difference is just water from lapping:

Before:

Attachment 334384

After:

Attachment 334386
Attachment 334385



EDIT: I've been looking at pics of these hone on Google/eBay/etc and many have the green hue but one on the bay had a chip on the top corner and was gray inside the chip, another had turned gray in the center where it had obviously been used to hone on. To me this lends more credence to the idea that some kind of compound was used to buff/rub the surface.