Friday, March 20, 2009
Gloriously Gold Filled!
for "Focus on Design" - The Jewelry Ring
by Cheri Van Hoover
Since ancient times, gold has been the metal most prized for jewelry. Soft yet durable, it can be shaped, etched, and rolled out into sheets just microns thick. It can be melted down and reused over and over again. Best of all, it never leaves black or green marks on your skin! Because it has been so highly prized, the price of gold has remained high throughout the millennia.
Pure gold is too soft to withstand regular wear, so early metallurgists learned to add other metals to gold to make it stronger. These metal alloys have included copper, silver, zinc, and nickel. In addition to making the gold stronger, these materials can also be used to change the color of gold. If copper is the controlling alloy, the gold is yellow or red. If the controlling alloy is nickel, the gold is white. An alloy of silver and zinc creates green gold. In addition to adding strength and altering color, these alloys make gold less expensive. Pure gold is called 24 karat. Other karat designations (10, 12, 14, 18) indicate the amount of alloy which has been added to the gold. For example, 14K gold is 14 parts pure gold by weight and 10 parts other metals.
Even in these lesser concentrations, karat gold is expensive. The 1742 discovery that silver could be fused to copper to create what became known as “Sheffield plate” set metalsmiths on a quest to develop a process for doing the same thing with gold. In 1817 an Englishman named John Turner discovered a technique for applying a thin layer of karat gold over base metal. He patented his discovery and entitled it: “Certain improvements in the plating of copper or brass, or a mixture of copper and brass, with pure or standard gold or gold mixed with a greater portion of alloy, and the preparation of the same for rolling into sheets.”
During the Victorian era larger pieces of jewelry were frequently made using this “rolled gold” technology, but standards regarding the quality and thickness of this plating did not yet exist. This lack of standards led to considerable variation in durability and appearance. The terminology used to describe this technique also varied. The rolled gold Victorian era brooch shown in Figure 2 is marked “GILT.” Rolled gold jewelry became less popular during the Edwardian era as fashions changed and jewelry became smaller and lighter. Delicate filigree became common. This type of jewelry was fairly affordable for the middle class without the use of plating. The economic boom times of the 1920s, combined with the demand for white metals such as platinum and silver, decreased the popularity of rolled gold even further. During the mid to late 1930s, however, a combination of social forces, economic hardship, government regulation, and changing fashions created a huge increase in the production of what had come to be called “gold filled” jewelry.
Price became an important factor for those buying jewelry during the Great Depression. Disposable income largely disappeared, and although women still wanted to adorn themselves they simply couldn’t afford the precious metal jewelry that had been popular in the previous decade. Fashions changed, as well. Beginning in the late 1930s, the style we now call Retro or Retro Modern replaced the Art Deco designs of the 1920s and early 1930s. Retro jewelry was big, bold, and consisted mainly of metals. Warm yellow and rose gold colors dominated the Retro styles, largely replacing the white metals of the Art Deco period. The United States Department of Commerce played a role in the new popularity of heavily gold-plated jewelry by issuing Commercial Standard CS 47-34 which created a precise definition for “gold filled,” decreeing that the total weight of gold filled jewelry had to be 1/20 or more (5% or greater) 10K or higher karat gold.
Gold filled jewelry is made from karat gold which has been bonded to the surface of a supporting base metal through a process of fusing and rolling. It is always marked with the karat designation and an indication that it meets the legal standard. Look for marks such as 1/20 12K G.F. or 12 Kt. Gold Filled. Rolled gold plate is also made by fusing and rolling gold onto base metal, but the plating is significantly thinner. Rolled gold plate may be marked 12 Kt. R.G.P. or 1/40 12K R.G.P. Another mark you will sometimes encounter is G.E., or gold electroplate. This is the thinnest of all gold plating techniques. The gold or gold alloy is not fused and rolled onto the base metal beneath, but rather plated in solution using an electrical charge to make the bond. By law, gold electroplate must be at least 7/1,000,000-inch thick, but this is extremely thin when compared with gold filled.
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Pictured above: Wedgwood Egyptian Pendant Necklace available at our CHShops online Mall Store at: Penny's Antiques & Wedgwood Pantry
Penny and Doug
Penny's Antiques & Wedgwood Pantry