I found this tiny "pebble" lying at a beach north of Chicago when hunting for interesting non-fossil beach rocks and sea glass. (Yeah, there are people who collect and love sea glass and "just rocks" :-)   So now, that I've started to collect coral fossils as well, mostly corals, I've been taking a closer look at some of my old finds and see all sorts of little fossil bits and pieces. This one when I found it, had caught my attention due to the tiny pattern, which I thought at the time