French platinum and diamond Art Deco pocket watch with enamel

• Onyx - Onyx is a form of agate, used from antiquity and popular again in the 1920s and 30s. European onyx is generally green, but can be many other colours, and can contain bands of black and/or white.
  
  This multicoloured stone is widely used for table tops, lamp bases and in jewellery. Some types of onyx are also used for cameos of which the upper white layer is cut away to reveal the colour beneath.
• Guilloche - A form of classical decoration consisting of a repeating ornament of interlacing curved bands, sometimes forming circles, and further decorated with rosettes or other flower forms.
  
  The name is derived from the inventor, French engineer Guillot, who invented a mechanical method of inscribing fine repeating patterns on to metallic surfaces.
  
  On enamelled items with guilloche decoration, the surface is firstly engraved with the repeating pattern, and then covered with several layers of enamel, each of which is fired.
  
  Where the item has not been enamelled the form of decoration is usually called "engine turned".
• Art Deco Period - The Art Deco period was a cultural movement that emerged in the 1920s and 1930s, and was characterized by its emphasis on modernism, luxury, and elegance. The name "Art Deco" comes from the Exposition Internationale des Arts Décoratifs et Industriels Modernes, a large exhibition held in Paris in 1925 that showcased the latest trends in decorative arts.
  
  Art Deco was a reaction against the ornate and elaborate styles of the previous era, and reflected a new modern sensibility. It was characterized by streamlined, geometric shapes, bright colours, and the use of new materials such as chrome, glass, and Bakelite. Art Deco designers sought to create a sense of luxury and sophistication, often incorporating expensive materials such as ivory, marble, and rare woods.
  
  Art Deco had a significant impact on a wide range of artistic fields, including architecture, fashion, graphic design, and interior design. Some of the most iconic examples of Art Deco architecture include the Empire State Building in New York City, the Hoover Building in London, and the Palais de Chaillot in Paris.
  
  The Art Deco period came to an end in the 1940s, as World War II and changing cultural trends led to a shift in artistic styles. However, Art Deco remains an important influence on design and art, and continues to be celebrated for its modernist sensibility and glamorous aesthetic.
• Lever Escapement - A lever escapement is a type of escapement mechanism used in mechanical clocks and watches to regulate the timekeeping of the movement. It was invented by British clockmaker Thomas Mudge in the 18th century and is now widely used in modern mechanical timepieces.
  
  The lever escapement consists of three main parts: the escape wheel, the pallet fork, and the lever. The escape wheel is a wheel with teeth that is driven by the clock or watch's main spring or weight. The pallet fork is a two-pronged component that is positioned so that it can engage with the teeth of the escape wheel, and the lever is a small, L-shaped component that is attached to the pallet fork.
  
  When the escape wheel turns, one of its teeth pushes against one of the pallet fork's prongs, causing the fork to pivot. As the pallet fork pivots, it releases the tooth and engages with the next tooth on the opposite side of the escape wheel. At the same time, the lever, which is connected to the pallet fork, rocks back and forth, allowing the escape wheel to turn at a regulated rate.
  
  The lever escapement is prized for its accuracy and reliability and is commonly used in high-end mechanical watches. It allows for precise timekeeping by ensuring that the movement of the watch or clock is regulated and consistent, and its compact size makes it an ideal choice for use in small, portable timepieces.
• A/f, as Inspected - The letters "A/F" or "as inspected" as part of a description is the cataloguer's shorthand for "all faults" or "as found", meaning the item has some type of damage or deficiency, it is of uncertain date or provenance, and/or that the seller takes no responsibility for the completeness of the item or the accuracy of the description.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.

This item has been included into following indexes:

• Breguet (brand) (Switzerland) - pocket watches and wrist watches 85
• pocket watches, case type
  • enamelled decoration 161
  • open face, silver case 570