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Yes, but you won’t know until you lap it. And it does not have to be 10k to finish. Very few natural stones are over 8k and still finish very fine.

As I said, depends on the price, for a dollar or...

Or badly, in need of lapping, depends on the price, I have certainly bought a boat load of black stones at garage sales and flea markets for a buck or two, and have ended up with a few clunkers, but...