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.

Because of my interest in theatre I have accumulated several history of costume books going back centuries. In the case of vintage jewelry my interests begin around 1840 to the 1960’s.

Jewelry construction has changed very little over the past 4000 years. It is a good idea to get a basic knowledge of jewelry construction and manufacturing techniques if you really want to accurately identify antique and period jewelry.

Hand Fabrication:
A piece is said to be handmade when a bench person makes the piece from start to finish. They may use purchased tubing or sheets of gold or may elect to alloy the metal and roll the gold themselves. The jeweler can start with a sketch of their own or one provided by a designer and then select the stones and materials or they can begin with the stones and let them dictate the size and flow of the finished piece.

Casting:
This method usually starts with an existing piece of jewelry or a carved wax form that a mold model can be cast from. A rubber mold is made by packing the model with a special rubber material and vulcanizing it in a mold maker.When it is finished the model is cut out and you have an exact duplicate of the orginal piece. How can you tell if the piece you are looking at has been cast? Look closely at the back side of the piece. Sometimes you can detect the tell-tale flow lines of casting or you may see a bubbly effect or porosity marks.

Die Striking/Stamping:
To be simply put die striking and stamping is the movable force(the metal) meeting the immovable object(the steel die). A designer creates an original by hand, then metal dies are made from the piece. The jewelry is manufactured by stamping the hard metal dies into the softer precious metal. Die-struck jewelry is denser and more durable than cast jewelry, and it allows a higher polish however, stamping is more expensive than casting because of the equipment, factory space and time involved in making dies.

Electroforming:
Compared to the previous processes this one is considered a “modern” process for making jewelry. It was first patented in England in the 1840’s. In the 1850’s and throughout the end of the century it was used to make copies of ancient and Celtic jewelry. Popularity for this process waned for almost 100 years but has now come back into favor.
It is basically a process in which pure or carat gold is electroplated onto a shaped former. This can be a low melting point metal but more recent technology developments now enable electroforming onto a wax model, such as produced for lost wax casting. Control of both consistency and uniformity of thickness as well as carat-age is very important in a mass production situation where 50 -75 pieces may be electroformed simultaneously in the bath. This is achieved by computer control of the plating bath. Generally electroformed articles will be around 100 -150 microns thick and even up to 250 microns for large items. The wax or metal former is removed at the end of the process.

There are 2 electroforming technologies available. One produces a deep yellow gold-copper-cadmium alloy deposit and the other a paler yellow gold-silver alloy, both in the range of 8 to 18 carats. Electroforming of pure gold is also carried out and is particularly popular in the Far East. When plating is done at high plating rates, a textured surface is produced which does not require further finishing.

White Metal Spin Casting:
Much of the costume or fashion jewelry made to day uses this method of construction. Because old costume jewelry is so collectible, it is important to have a some understanding of how it is made.
The white metal used in this process is an alloy or mixture of tin, lead, bismuth, antimony and cadmium. The tin content can vary from 17-92% depending on the quality of the piece. Many good quality white metal pieces have an 88% tin content. White metal melts at 520 to 420 degrees. Just like other casting methods this one starts with a model of the piece to be produced. From this piece a model mold is made. Since 1937, rubber was the choice material for molds. Before that year the molds were made of bronze.

I get asked this question a lot. And I have a few different avenues of research that I pursue when trying to “date” a particular piece.  One way is by looking at jewelry ads from old fashion magazines like this ad for Corocraft from 1957. Magazines are a wonderful way to  ”date” pieces because they will have dates on them and you can tell the approximate date of a piece by matching it to an ad.

Some vintage jewelry pieces have patents on them. This means they have a registered patent number which can be researched to determine the registration date. 

Google  has a new tool called “Google Patents” which contains a search-able data base of all US patents registered from 1790 to 2006. 

Another thing to look for would be a Copyright. In 1956 it became much more cost effective for designers to register a copyright on a design rather than go through the costly  patent process. Pieces bearing a copyright symbol indicates that it was produced in 1956 or later.

You can also look at the makers mark or signature on a piece. For example: The Schreiner Company of New York. Henry Schreiner immigrated from Bavaria Germany to the United States in 1923.  In 1939 Henry opened his own company based in New York.His daughter Terry and her husband Ambrose Albert joined the company in 1951. Henry died in 1954 and his daughter and son in law continued the business until 1975. Signed Schreiner pieces were marked with  “SCHREINER NEW YORK” in all capital letters in an oval. Some times designers did not sign their pieces. Henry Schreiner started out working for Christian Dior before opening his own company and his early pieces are not signed with his name. You can tell it was one of his designs because Henry Schreiner had a very distinctive style.

Another way to date a vintage piece of jewelry is by the style of the piece. Knowing what styles were popular over the years is very helpful.  Again  fashion magazine ads from past years are helpful as are history of costume books.