Zam

There is a u-tube video
where the person goes through the step of grinding a cab
he buffed this stone with Zam
to me it seemed counter intuitive
cause the stone was some sort of agate
and I usually use Zam for softer stones
serpentine and such

although as a final finish on a hard stone
it doesn't seem to hurt
a warm stone seems to help
maybe it just a polishing wax compound ?
I use a cotton buff on my Foredom for this

I've look into the technical data on zam
and it does have some abrasive quality
it great on brass

that u-tube video is worth checking out

I don't know much about Zam, but I use it on Petoskey Stones, which are soft. I also heard that it is an abrasive used on soft metals and stones.

I was in a Petoskey Stone shop in the town of Petoskey recently. The lady there showed me her shop and explained how she does her stones. She only works with Petoskey stones, nothing else. The shop was green with Zam dust. After using a 600 grit wheel, she uses a soft buffing wheel with Zam as the last step. I do the same thing, but I use a small cotton wheel on my Dremel to polish with Zam. It makes a huge difference on Petoskeys.