Mae West 1930’s publicity still from Paramount Pictures.

Unfortunately not all vintage jewelry is signed. This doesn’t mean the piece isn’t worth something. It means you have to do your homework and research. Knowing what the styles were is very helpful in dating a piece. Jewelry styles changed in accordance with changes in hairstyles and clothing as well as world events.
1920-s to 1940’s
The 1920’s saw shorter hair, shorter skirts and a looser style of clothing for women. It was the “Modern Age” - bracelets in bold angular designs were seen on the arms of “Modern Women” as were long necklaces that ended in tassels and sparkly cocktail rings. Everything was all angles and lines were very “boyish”.
The 1930’s brought back feminine curves and artfully applied makeup. Hair styles were sleek and upswept. Moving pictures and movie stars were a huge influence in fashion.
Art Deco is a style that relates to 1920’s-1930’s, which ended about 1935. The Art Deco movement was mainly an American thing. The style of jewelry had strong lines, bright contrasts of color and geometric shapes. Bakelite became a very popular choice of material for creating fashion jewelry.
During this time period jewelry design was influenced by Japan, Paris, the machine age, Ancient Egypt (discovery of King Tut’s Tomb), jazz, cubism and Russia. Art Deco was also influenced by the Art Nouveau and Edwardian periods. Taking the style and grace from Art Nouveau; diamonds and platinum from the Edwardian period, designers turned jewelry into a geometric, symmetrical array of diamonds and platinum.
Art deco had great vibrant colors, sapphires, emeralds; coral, rubies and turquoise were heavily used. Black and white was also used a lot. Cocktail rings, long pendants, brooches and bangle bracelets were all the rage.
Cigarette cases and compacts of the time were covered in jewels. The movement of art deco halted because of WWII and the depression.
The end of the First World War marked the start of the popularity of costume jewelry. Fine jewelry at the time had unpleasant associations with being frivolous and unpatriotic. The new fashion for women was casual as well as sporty, and was not very well suited to the formality of precious gemstones. The Art Nouveau movement had already prompted a change in perception towards jewelry, focusing attention on aesthetic rather than monetary value. In the postwar period, the major couturiers took this one stage further by initiating the trend for entirely non-precious jewelry.
The 1930’s and 1940’s brought about the retro period. Large gemstones were being used. Topaz, citrine and aquamarine were popular. Even synthetics were starting to become popular. Platinum was replaced by rose gold.