Band under lip is from Costa Rican area where plates are under such great pressure and friction that the sediment there melts from the heat of it. Lower material is from the Mid-Atlantic Ridge where drillings into Earth's crust were taken, cut, and resulting slurry was given to me . . . a science writer gave me the word "remagmized" to describe what happens to this slurry in the kiln.
Interior glaze assembled from refined materials and red glass is used in the thumbwell -- I chose red as a glimmer of the Earth's interior heat.