...maybe the middle to, I think the middle section is....quartz/chalcedony? the middle does not scratch with a steel knife and it does scratch glass, it showed no streak on a white tile. the rocky white layer on top also does not scratch with a steel knife and showed no streak. The bottom thin layer scratches easily and is rough in texture, it streaks white. I think I found this one in some landscape decorative stone but cant be sure, I have had it a couple of years. Thx.