The two-dimensional representation of the urn and the regular positioning of the background tesserae suggest that this is an early micromosaic, about 1800. The long octagonal bezel is typical of rings of this date. Contemporary mourning rings can be found with similar urns made of gold or painted on ivory.

The term 'micromosaic' is used to describe mosaics made of the smallest glass pieces. Some micromosaics contain more than 5000 pieces per square inch. The earliest attempts at micromosaic revealed visible joins between the pieces (known as tesserae) and a lack of perspective. Later artists such as Antonio Aguatti made huge advances in micromosaic technique, resulting in renderings that were truer to life. Glass micromosaic technique developed in the 18th century, in the Vatican Mosaic Workshop in Rome, where they still undertake restoration work today.

Sir Arthur Gilbert and his wife Rosalinde formed one of the world's great decorative art collections, including silver, mosaics, enamelled portrait miniatures and gold boxes. Arthur Gilbert donated his extraordinary collection to Britain in 1996.