I got these very cheap stones from ebay expecting them to be garbage but I'm not so sure. They came flat, sealed, and free of all toxicity it seems so far. I know nothing about jnats but these rocks seem pretty abrasive to me but I haven't explored their fineness. I have no idea about layers, fineness or even what the names mean so any advice or direction would be great. I can hone just about anything on many different types of stone but I'm new on this. It's what makes things exciting. I think i understand completely HOW they are to be used(as a know nothing commenting on a 1k+ year old art) but I'd like to be able to interpret the stone in my hand, especially if there are ways other than rubbing steel on stone(I want to learn these particulars too). The stones are pretty and honestly if I had gone to harbor freight it some other garbage pit they'd probably cost more. They got from Japan to Texas in 2 days. I'm scared I'm going to begin buying more steel to sharpen.