Scotch Stones vs. Ruby Stones

Does anyone know the differences between scotch stones and ruby
stones? I’ve never used either. I’m guessing that ruby stones are
harder.

Thanks,
Jeff Georgantes

Does anyone know the differences between scotch stones and ruby
stones? I’ve never used either. I’m guessing that ruby stones are
harder.

Ruby stones are exactly that synthetic ruby. Aluminum oxide. Hard,
rigid, a wonderful abrasive. prepared flat ruby stones in various
grits are available, and wonderful for sharpening gravers.

Scotch stones are very different. They’re a natural stone, I think a
type of soft very fine grained slate. Wonderful for smoothing
defects in jewelry metals, since with a little water, stoning
quickly wears down the scotch stone to conform with the surface being
dressed, so you don’t dig grooves. Great for things like removing
pesky solder scars in those blind corner areas where no rotary tool
will work and your darn graver somehow managed to also dig some still
visible striations…

cheers
Peter Rowe

Scotch stone is prolly more like a sandstone jasper, ruby stone is
corundum! That makes 6 on one and 9 on the other…hardness.

Ringman