Anybody have any ideas as to what this might be?

Getting ready to try some slurry finishes with the new lighter eNat stone so I did a quick test with the HSS test piece on the convex bevels to compare the slurry finish from the eNat stone to my very hard and fine JNat Asagi that I got from a seller in Japan. Both shots are through my 30x optical microscope.

eNat slurry finish - prefinished with 5k Suehiro, then 300 laps (only 1.5" long and on convex bevel) medium pressure, then 150 laps very light pressure on medium heavy slurry:

Attachment 184191

JNat slurry finish, same conditions as above:

Attachment 184190