testaceous
adjective
°(obsolete) Pertaining to earthenware or baked clay.
"1658: they were burnt, or only baked in Oven or Sunne: According to the ancient way, in many bricks, tiles, pots, and testaceous works — Sir Thomas Browne, Urne-Burial (Penguin 2005, p. 20)"
°Having a shell, especially one which is not articulated.