1964 Rolex GMT-Master Ref. 1675 Dual-Time Wristwatch

• Bezel - On a clock or watch, the bezel is the metal frame into which the watch or clock glass is fitted. In clocks, the bezel may include a hinge and a flange, in effect a door to the face of the clock. In jewellery the bezel is a band of metal with a projecting lip that holds the gemstone in its setting.
• Back Plate - On many types of clocks, the movement operates between two plates, usually made of brass, one at the back, and the other at the front, which forms a mount for the dial.
  
  On English bracket, mantle and table clocks the backplate was often visible through a glass door or panel from the late 17th century, and could be profusely engraved with scrolling decorations, flowers, foliage, birds, and figures. The engraving could also include the maker?s name.
  
  The amount of engraving reduced and became simpler as the 18th century progressed, and by 1800, had been reduced to a border, often with the maker's name in the centre. By the early 1800s all decoration had ceased, and only the maker's name was added, and by the Victorian era, most bracket, mantle and table clocks had no engraving.
• 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.
• Movement - The technical name for the workings of a clock or watch, and does not include the dial or case.
• Bakelite - Bakelite was the first completely synthetic man-made substance. Bakelite was invented in 1909 by an independent New York chemist Leo H. Baekeland. It was called the "material of a thousand uses" and used to make everything from car parts to jewellery.
  
  Although nearly all plastic from this period is known as ?Bakelite', it is important to remember that this is an umbrella term that covers many different early plastics such as Lucite and cellulose acetate, and includes Bakelite.
  
  We often think of the colour of Bakelite items as dark brown, but it was manufactured in various colours including yellow, butterscotch, red, green and brown.
  
  Bakelite could also be transparent, or marbleised by mixing two colours. Plastics were cheap to produce and could be moulded or carved in a huge variety of ways.
  
  Bakelite is most commonly associated with radio cases of the 1930s, telephones and kitchen utensils, but it was also used extensively in jewellery manufacture.
  
  Early designs from the 1920s were plainer and simpler than later examples. Geometric and floral patterns typical of Art Deco styling were popular.
  
  During its heyday in the 1930s, Bakelite jewellery was stocked by the most prestigious stores, such as Saks, Harrods and Macy?s, who dedicated a shop window display to it in 1935.
  
  Coco Chanel featured Bakelite items in her accessories collection and the material was praised frequently in Vogue magazine.
  
  Manufacture of some consumer Items were suspended in 1942 in order to concentrate manufacturing on the war effort.
  
  Small items made of Bakelite are now valuable collectables. Andy Warhol was an avid collector, and when he died in 1987, his pieces sold for record prices at Sotheby's.

This item has been included into following indexes:

• Rolex, other models - wristwatches 239