Center: sandblasted in amphibolite (crinoid -Pycnocrinus, Upper Ordovician, Cincinnatti, Ohio; crinoid – Petalocrinus, Middle Silurian, Iowa; cystoid – Lepadocrinites, Silurian, United Kingdom), outer ring: laser etched in amphibolite (cystoid – Pleutocystes, Ordovician; echinoderm – Edrioaster, Ordovician, Trentonian, Canada; starfish – Villebrunaster, Lower Ordovician, France), tumbled jasper, onyx, core buttons of hornblende gneiss and microcline gneiss