Are these stones a slate or more like novaculite? Because my mystery green stone has lines on it like @timwic original picture but as I lapped it they disappeared and turned into a single dot. Initially I thought it was a Charnley but no red, and it's very different from my llyn idwal hones. It seems to be Flakey like turkey stones are but I haven't had any obvious ones flake off yet. I just want to know what it is so I can invite it's extended family into my home like the nurturing person I am. As far as I can tell though these are very slate like similar to a thuri.Wife's out this evening... I sense a deep-dive into the bathroom cabinet coming on .