Now in almost complete ruins, the Joi Burj, or 'blue tower' is a circular fired brick structure upon a stone base, with a dodecagonal interior. Fragments of tile ornamentation include mosaic faience, unglazed strapwork, and tiles with glaze removed to expose the biscuit.
Source:
Donald N. Wilber, The Architecture of Islamic Iran, New York: Greenwood Press, 1969, p.174-175
