Looking at earlier stones I worked I think I can see why the tripoli worked out fine.
My first stones were translucent and had silk/intrusions that didn't reach the surface of the stone. They also tended to be agate or feldspar.
The next large group had several stones with silk/intrusions that reached the surface, aggregated quartz stones (not a proper name, but the stones appear to be composed of small quartz crystal stuck together), and stones that were a mix of quartz and other material (most often thin black squares that I think are mica).
The end of my found rocks are a mix of translucent and opaque (a few look a little like marble).
I think the tripoli has issues with stones with silk/intrusions that reach the surface. In sanding, the diamond tends to reveal silk/intrusions that run deep and, with additional work, lessens them. The tripoli tends to widen the gaps. With additional work the tripoli does lessen them but it would take a great deal of work to remove them.
In the case of stones that have softer material mixed in, the tripoli attacks the softer while barely touching the harder. Additional work with the tripoli makes things worse.
At this point I think the tripoli creates more work with mixed material stones and stones that have silk/intrusions that reach the surface.
I think I'll use a heavier mix of tripoli for polishing to see if that will work better and to use it up faster so that I can move to diamond for my 1200 grit step.
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