Yellow Diamond Single-Stone Ring, 1970s

• 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.
• Collet Setting - A collet setting in jewellery is a type of setting that is used to hold a gemstone or other decorative element securely in place. The collet is a ring of metal that surrounds the stone and holds it in place. The collet is typically made of the same metal as the rest of the piece and is often used in vintage or antique jewellery.
  
  In a collet setting, the gemstone is placed into a small metal ring, also known as a collet. The metal ring is then bent or folded over the edges of the gemstone to hold it securely in place. The collet is then attached to the rest of the piece of jewellery, such as a ring or pendant.
  
  One of the benefits of a collet setting is that it allows the maximum amount of light to enter the stone, which can enhance its brilliance and sparkle. It also allows the stone to be seen from the sides, which makes it a popular choice for showcasing particularly beautiful or unique stones.
  
  The collet setting is a classic and elegant setting and it is often found in antique jewellery, particularly from the Victorian and Edwardian periods.
• 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.

This item has been included into following indexes:

• rings, diamond - diamond, multiple diamonds 5,033
• rings, diamond solitaire - diamond solitaire / claw set brilliant cut 6,883