Very likely a Llyn Idwal, but its hard to say. Is it heavy for its size?The green was a bit challenging to flatten as it was going very slow. I ended up wetting smooth concrete and doing the first stage there. I probably lost more stone but it did make it go faster. I went to a 300 diamond after the concrete. I have yet to figure out what it is, but it has silica like sparkles when dry
ALSO, I'd suggest picking up one of the ~$20 Diamond plate "card" sets on Amazon. You can use the higher grit(800-1000+) grit cards to raise a slurry on the Escher and the "Llyn Idwal," and the 400-600g on your BBW.