Opal Ring in 9ct Gold, Birmingham 1919 - Size J

• Cabochon Cut in Jewellery - A cabochon cut is a type of gemstone cutting where the stone is cut and polished in a convex shape with a flat bottom and a domed top, with no facets. This type of cut is typically used for opaque or translucent stones that have natural patterns or inclusions that are best displayed in this type of cut. Examples of stones that are often cut as cabochons include turquoise, opal, and moonstone.
• 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.

This item has been included into following indexes:

• rings, various gems / stones - opal 811