Diamond and Paste Bat Brooch and Pendant Set

• Paste / Rhinestone / Diamante - Paste (or rhinestone or diamante) is the name given to a coloured glass composition used for imitation gemstones, or to imitation gemstones made of glass.
  
  Although the technique of glassmaking had been known for thousands of years, but it wasn't until a lead glass with similar optical properties to diamonds were invented by a German jeweller working in Paris (either "Stras" or 'Strasser") in the early 18th century that "paste" gemstones became popular.
  
  There was no social stigma attached to wearing imitation stones, and they were worn in situations where highway robbery was a possibility. The 18th century settings were of very high quality, equivilent to real gemstone jewellery.
  
  In the nineteeth century the quality of paste jewellery declined and it has remained the poor cousin to genuine gemstones ever since.
• Art Nouveau Period - The Art Nouveau period was a cultural movement that emerged in the late 19th century, and was characterized by its emphasis on natural forms, flowing lines, and a decorative, ornamental style. Art Nouveau was a reaction against the ornate and heavily stylized designs of the previous era, and sought to create a new, more organic aesthetic.
  
  Art Nouveau was characterized by its use of sinuous, curving lines, as well as a focus on natural elements such as flowers, vines, and other organic shapes. Art Nouveau designers sought to create a total work of art, in which every element of a building or object was designed to be harmonious with the overall design.
  
  Some of the most iconic examples of Art Nouveau design include the Paris Metro entrances designed by Hector Guimard, the works of the artist Alphonse Mucha, and the architecture of Victor Horta in Brussels.
  
  The Art Nouveau period was at its peak between 1890 and 1910, but began to decline in popularity by the start of World War I. However, Art Nouveau remains an important influence on design and art to this day, and continues to be celebrated for its emphasis on natural forms and decorative style.
• 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.
• 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.
• Rose Cut - A flat based cut for a preious stone, leaving the surface covered with triangular facets, usually 24 in total.
  
  It was introduced in the 15th century and popular during the 16th and 17th centuries.
  
  The rose cut was the most popular form of diamond cut until the discovery of the brilliant cut at the end of the 17th century, after which its use declined.
• Plique-A-Jour - Plique a jour, which translates from the French as ?glimpse of daylight? is a method of enamelling in which the backing is removed or cut away so the light shines through, with a similar effect to a stained glass window. The enamel is held in place by border.
  
  Although the technique of plique-a-jour has been known and in use since the 6th century, it became popular again in the late 19th century, in Russia and Scandinavia. Plique-a-jour was popular in the Art Nouveau period, especially for jewellery.
  
  Because of the length of time required to produce an item, and the high failure rate, production was limited, and the technique is little used today.

This item has been included into following indexes:

• Art Nouveau jewellery - brooches, period or age 127
• brooches, crescent - crescent, with diamonds 87
• brooches, diamond
  • diamond and enamel 143
  • diamond and pearl 405
• brooches, gold
  • gold with enamelled decoration 411
  • gold with pearls 957
• brooches, other - with locket 783
• brooches, silver - silver items 2,659
• plique a jour - jewellery and objects 96