In spite of the ever increasing interest in Islamic ceramics, information on kilns, moulds and other related objects is still relatively scarce. What is known is that moulds were used even before the creation of fritware, for the production of lead glazed relief ware during the early Abbasid period (8th-9th centuries CE), and always were made of red or buff earthenware. A reliable attribution of provenance and dating is quite a difficult task, since the actual place whence these moulds originated is not known.

The moulds can be typologically divided into two groups: moulds for the interior of the vessel and moulds for the shaping of the exterior of the vessel. The mould here illustrated is made of red earthenware in a hemispherical form, the outside carrying the bas-relief decoration,consisting of a concentric epigraphic band of plaited characters. The cavetto was left undecorated, while the upper sides feature a row of vertical small palmettes in bas-relief.

It is clear that it was used for the interior decoration of a bowl of similar size.
For a discussion on moulds see:
G. Fehervari, Ceramics of the Islamic world, 2000: p.335-45.