Shell from various molluscs have long been used for jewellery. Shells develop in layers and so some shells like the conch and the helmet shell are used to carve cameos as they have pink, white and sometimes brown coloured layers which are carved away. Shells like the cowrie shell are used as beads. Other shells have nacreous layers, like the abalone shell and the New Zealand paua shell, which make beautiful buttons and jewellery, while the trochus shells are used to make mother-of-pearl products.
Some of my favourite jewellery is made from opercula, which are little trapdoors used when a mollusc moves back into its shell. The opercula from turban shells in particular have lovely circles of green and brown on a white background.
A different king of shell used in antique jewellery is tortoiseshell, from hawksbill turtles mainly. Tortoiseshell is listed on CITES and trade in it is now banned. Tortoiseshell has been used for decorative items for a long time. It was favoured by the Romans but it was particularly popular in the 17th and 18th centuries for veneers for furniture and for objects like snuff boxes and card holders.
The use of tortoiseshell for jewellery rather than for small decorative objects and accessories reached its popularity in the 1860s. Two types of inlay work were done, using a technique called ‘pricking’ which became ‘pique’. The first, pique point, was when small wires were pushed into tortoiseshell softened by heat, and then filed off flush to the surface, leaving dots, stars or similar small shapes. The second, pique pose, pressed strips of gold or silver metal arranged into floral or geometric patterns.