The subject, the Pantheon in Rome, is typical for Grand Tour material of this early 19th century date but it carries the signature of Joachim Barberi, one of the very best mosaicists working in Italy at the time. Some of his mosaics contain more than 5000 pieces per square inch.
Measuring 2¾ x 1¾in (7 x 5cm), the original silk-lined case is set with the maker's card Joachim Barber, Professeur de Mosaique, Place d'Espagne Ho. 97, 98, 99, et Rue de la Croix No. 1, Rome, while the back of the gilt frame is inscribed To Mrs Main of ***, from J.H. Anderson, 1831.
"The quality and intricacy of the plaque was astounding," said Mr Wyrley-Birch. "To the naked eye it looked like a miniature painting and even with a jeweller's loupe it was hard to make out the individual tiles. It's the best I have seen."
Offered at the March 26 sale on behalf of a resident of Corbridge, Northumberland with an estimate of £800-1200, it sold to an Italian telephone bidder for £6200.
Remarkably, it is the second Joachim Barberi plaque to be offered in recent months. Lindsay Burns Perth sold another depicting a gun dog and ducks on December 4 for £6100.
The buyer's premium at Anderson & Garland was 19.5%.