Check out these pics:

Name: Picture 001.jpg Views: 268 Size: 18.3 KB

Name: Picture 003.jpg Views: 266 Size: 17.6 KB

Name: Picture 010.jpg Views: 272 Size: 30.8 KB

Name: Picture 014.jpg Views: 284 Size: 33.6 KB

Name: Picture 019.jpg Views: 263 Size: 28.4 KB

Name: Picture 015.jpg Views: 265 Size: 33.1 KB

I bought this stone recently at a garage sale for $2. It was about 12" long by 2.5" wide. Originally it was used in a diesel repair shop and was mounted to a work station by some screws (screw holes drilled into each end of this stone). It was used to lap diesel injectors flat. Nowadays a diesel shop owner I know says it's typical to use a metal surface plate and fine lapping compounds.

It seems to be a mudstone of some variety. It's a hard stone, but the ends cut off fairly easily using a tile cutting round hack saw blade (2 slurry stones ya know). It's surface feels ultra smooth, definitely as smooth as coticule or Thuringian. The slurry stones do produce slurry easily. It does polish steel, but I've only had the time to do some passes with a razor needing a honing job.

It's colors are beautiful purples and grays with that very interesting black eye inclusion.

Howard Schechter viewing the same pictures thought it could be some sort of Wa****a Arkansas stone variety. He said the Wa****as came in a variety of colors. I thought Lily White Wa****as were classed at approx 1K grit. This stone is much much finer than that and is definitely only a polishing stone.

So.........any guesses?

Chris L