Art Deco Opal and Guilloche Sterling Silver Compact, 1936 Birmingham

• Marcasite - Marcasite is a mineral, iron sulphide, but is rarely used in jewellery. Instead marcasite is the name given to iron pyrites, the mineral sold as marcasite which is identical in copmosition to iron sulphide but crystalises as a cube, making it more suitable for jewellery. It is a brassy yellow in colour and is also known as "fool's gold", and sits well with silver rather than gold becasue of its colour.
  
  Marcasite has been used in jewellery since ancient times and became popular again in jewellery in the 18th century, continuing through to the early 20th century, with the settings becoming cheaper as time progressed, eventually earning the sobriquet "costume jewellery" along with other cheap jewellery that was made for a prevailing pattern and meant to be changed with each new outfit.
• 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.
• Engine Turned - Engine turning is a decorative technique used on metal surfaces to create intricate curving or geometric pattern. The process involves cutting a series of lines into the surface of the metal using a rose engine or decoration lathe which rotates the metal as it cuts, allowing the operator to create a repeating pattern that covers the entire surface. The resulting surface has a shimmering, reflective quality that is often described as "engine turned." Where an engine turned item has been enamelled, the term used to describe the decoration is usually guilloche.
  
  Engine turning was originally developed to decorate metal objects such as firearms, scientific instruments, and other metal objects that required precise and elegant design.
• 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.
• Sterling Silver - Sterling silver is a mixture of 92.5% pure silver and 7.5% of another metal, usually copper. Fine silver is 99.9% pure silver, and is relatively soft and the addition of the very small amount of copper gives the metal enough strength and hardness to be worked into jewellery, decorative and household objects.

This item has been included into following indexes:

• Adie Brothers (Birmingham) - silver, maker or retailer 115
• compacts - enamelled 74