Antique French Ormolu and Mother of Pearl Casket c.1870 19th C

Ormolu - (from French 'or moulu', signifying ground or pounded gold) is an 18th-century English term for applying finely ground, high-carat gold in a mercury amalgam to an object of bronze.The mercury is driven off in a kiln leaving behind a gold-coloured veneer known as 'gilt bronze'.

The manufacture of true ormolu employs a process known as mercury-gilding or fire-gilding, in which a solution of nitrate of mercury is applied to a piece of copper, brass, or bronze, followed by the application of an amalgam of gold and mercury. The item was then exposed to extreme heat until the mercury burned off and the gold remained, adhered to the metal object.

After around 1830 because legislation had outlawed the use of mercury other techniques were used instead. Electroplating is the most common modern technique. Ormolu techniques are essentially the same as those used on silver, to produce silver-gilt.
 

Nacre
also known as mother of pearl, is an organic-inorganic composite material produced by some molluscs as an inner shell layer; it is also what makes up the outer coating of pearls. It is strong, resilient, and iridescent. The outer layer of pearls and the inside layer of pearl oyster and freshwater pearl mussel shells are made of nacre. 

Both black and white nacre are and were used for design purposes. They were used as decorative motif used in cabinet making or silversmithing. The natural nacre may be artificially tinted to almost any colour. Nacre tesserae may be cut into shapes and laminated to a ceramic tile or marble base. The tesserae are hand-placed and closely sandwiched together, creating an irregular mosaic or pattern (such as a weave). The laminated material is typically about 2 mm thick. The tesserae are then lacquered and polished creating a durable and glossy surface.