Australian Gold Signet Ring by J Henry Steiner (1880)

• 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.
• 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.
• Cartouche - An ornamental panel in the form of of a shield, oval or rectangular scroll with curling edges. It may be carved into the back of a chair or the top of a sideboard, or present on a piece of silver or jewellery, and contain the initials of the original owner, heraldic symbols, or some other inscription, such as the details of a presentation.
  
  In ceramics the term defines the central area of a vase or similar with a decorative border in one of the shapes above, into which a decorative scene or figures have been painted.

This item has been included into following indexes:

• rings, types - signet 706
• rings, various gems / stones - gold not diamonds, other types 5,170
• Steiner, Henry (Adelaide, Australia) - jewellery 22