Boucheron Aquamarine Diamond Buckle Brooch

• 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.
• 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.
• Carat - A carat (abbreviated "ct") is a unit of measurement used to describe the weight of a diamond or other gemstone, and separately is a unit of measurement used to describe the weight of precious metals such as gold,.
  
  For gemstones, one carat is equal to 0.2 grams or 200 milligrams. The weight of a diamond is one of the Four Cs (along with cut, colour, and clarity) that are used to determine a diamond's value.
  
  It is important to note that a diamond's weight does not necessarily correspond to its size. A diamond's cut, which affects how well it reflects light, can make a diamond of a lower weight appear larger than a diamond of a higher weight. Additionally, the carat is not the only factor to determine the value of a diamond, other factors such as clarity, colour and cut are important too.
  
  In the gold industry, the purity of gold is measured in carats (abbreviated "ct"), with 24 karats being pure gold and lower carat numbers indicating a lower purity level. So, for example, 18 carat gold is 18/24 or 75% pure gold, and 12 carat gold is 12/24 or 50% pure gold.
• Palmette - A decorative motif used in the decoration of ceramics, textiles and furniture, based loosely on the palm leaf and sometimes used with the anthemion, from which it is often difficult to distinguish. The form of the palmette varies from ornate to simplistic.
• Claw Set Jewellery - The description "claw set" in jewellery refers to a setting where the gemstone is held in place by metal prongs that resemble claws. These prongs are bent over the edges of the gemstone to secure it in the setting. This type of setting is commonly used for diamonds and other precious stones.
  
  

This item has been included into following indexes:

• Boucheron (France) - jewellery 35
• brooches, diamond - diamond and aquamarine 27
• brooches, set with - diamonds 511