I found this lying on the seashore under the cliffs between Aberystwyth and Borth. Its about the size of a mobile phone. It looks like a fossil of some kind of grass in slate/mud stone? Does anyone know what it might be or how old? I'm intrigued..... any response greatly appreciated, Thanks
There are both fossils (mainly plants) and minerals that can look like that.
My best guess is that the rock fractured, that happening in a such a way that a frondescent pattern formed (it is due to the nature of crack propagation). The fracture then became filled with (pale) minerals - turning it into a vein., Then much more recently, the rock split along that vein and erosion wore away some of the mineral, leaving just a smear, preserved in the slight relief of the earlier frondescent fracture pattern.