Onyx and Diamond Panthere Earrings by Cartier

• Openwork in Jewellery - Openwork, also known as pierced work, is a decorative technique used in jewellery making that involves removing or cutting out sections of metal from a piece of jewellery to create a pattern or design. This technique can be used in a wide range of jewellery styles, including necklaces, bracelets, earrings, and rings.
  
  Openwork jewellery can be made using a variety of different techniques, including hand carving, sawing, and laser cutting. The design can be simple or complex, and can feature a range of different shapes and motifs, from delicate floral patterns to bold geometric designs.
  
  One of the advantages of openwork jewellery is that it can add visual interest and depth to a piece without adding a lot of weight or bulk. This can be particularly appealing in larger pieces, such as necklaces and bracelets, where heavy materials can be uncomfortable to wear.
• Circa - A Latin term meaning 'about', often used in the antique trade to give an approximate date for the piece, usually considered to be five years on either side of the circa year. Thus, circa 1900 means the piece was made about 1900, probably between 1895 and 1905. The expression is sometimes abbreviated to c.1900.
• Assay / Assayed - Assaying is the testing of a metal, most commonly silver and gold to determine its ingredients and quality. In Britain, once an item of silver or gold has been assayed, a mark is stamped on it, certifying its purity. Known as hallmark, it derives its name from the Guild Hall of the Goldsmiths' Company, who recieved its Charter in 1327 giving it the power to assay and mark articles of gold and silver.
• 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.

This item has been included into following indexes:

• Cartier (France), jewellery
  • earrings, designers 104
  • Panthere jewellery 66
• earrings, gold - gold and black diamonds 354