Essex crystal pieces are formed from a rock crystal cabochon (polished domes of rock crystal with a flat base), an image or motif is then reverse carved into the flat base, and then painted, to give them impression of a three dimensional object or image encapsulated in the cabochon when viewed from above. This process of carving into the back of the cabochon is sometimes referred to as reverse intaglio, not be to mistaken with intaglio, which is designed to be viewed from the same side on which it is carved, unlike Essex crystal. Animals, hunting scenes and flowers are the most common themes, occasionally nautical motifs also. Traditionally they were backed onto gold foil and later etched mother of pearl or plain mother of pearl, before being set in their respective pieces of jewellery.