These are tesserae, small tiles used to create mosaics, from the Mosque of Omar, Jerusalem.
Made from several different coloured stones, green and blue glass. Some of the tesserae are covered in gold leaf.
The Mosque of Omar is an important Islamic religious site in Jerusalem, famous for its minarets (tall towers) and intricate mosaics.
Built in 1193 by Saladin, it replaced an earlier mosque of the same name, constructed by Caliph Omar (AD 579-664) which was located nearby.
These colourful mosaic tiles (tesserae) are believed to come from one of these two sites. They were donated to Folkestone Museum by Mr S A O MacKenzie.