unvitrified

/ʌnˈvɪtrɪfaɪd/
adjective
  1. Not converted into glass or a glass-like substance by heat.
    • The pottery was left unvitrified, so it remained porous and fragile.
    • In the kiln, some tiles came out fully glazed while others were unvitrified.
    • The ancient bricks were unvitrified, which explained why they crumbled so easily.
Antonyms
What does "unvitrified" mean? | whatsthatwordmean | whatsthatwordmean