Alabaster panel depicting the head of St John the Baptist surrounded by saints. Alabaster, a fine grained form of gypsum, is a smooth marble-like stone that became popular during the late Middle Ages for the carving of religious sculpture. Softer than marble, it was much easier to carve and also considerably cheaper. England was an important European centre of alabaster production, with quarries outside Nottingham, York, Burton-on-Trent and London. From about 1380s, alabasters - both single devotional images and reliefs for altarpieces - were exported in considerable numbers to the continent where they were to survive, whereas in England such images were destroyed during the Reformation.

There are two sorts of alabaster. Calcite alabaster is very hard and was used in ancient times. This object is made of gypsum alabaster which is a fine-grained, soft and smooth stone. Although at first glance it looks a little like marble, which it was intended to imitate, it was much easier to carve due to its softness, and alabaster objects were therefore significantly cheaper to produce.