Pocketwatch 101 – Learn about Vintage and Antique Pocket Watches

Materials Used to Make Vintage Watch Cases

How to tell if your vintage watch case is gold or gold-plated?

What metals were commonly used to make watch cases? Is every gold-colored case watch case made of gold? Are all silver-colored watch cases made of silver? Answers to these and many other questions about watch case materials can be found below.

Solid Gold Watch Cases

If your vintage pocket watch is in a gold-colored case, odds are pretty good that your case is gold-plated or gold-filled, or even just gold-colored metal. There were far more gold-filled cases made than solid-gold "karat cases"... in fact, it is estimated that only about 5% of cases produced were solid gold. These days, solid-gold cases have become even more scarce because so many of the large gold cases have been sold or melted-down for their gold-value (a practice we abhor and discourage, by the way). But there were some beautiful, solid-gold cases made over the years and some of them have survived intact. So if you have a vintage watch that's housed in a solid-gold case, consider yourself lucky!

It's important to understand the difference between "solid-gold" and "pure gold". Solid-gold means the case is gold all the way through. Pure gold (100%) with no other metals added is called 24-karat, but pure gold would be much too soft to be useful as a metal for making watch cases. Gold must be mixed or "alloyed" with other metals to make it hard enough to be usable. The purity of gold is expressed as a fraction of "pure" 24 karat gold, so if something is marked as 12-karat gold, that means it is 12/24ths or 50% gold. Gold coins are about 22K (91.6%), and the highest purity typically found in jewelry or watch cases is 18K (75%) which was fashionable in Europe. Most solid-gold watch cases sold in the USA were 10K - 14K (41.6% and 58.3%, respectively).

Gold Case Markings

If a watch case is solid-gold it will usually be hallmarked or stamped with a karat symbol or assay mark, like "WARRANTED U.S. ASSAY". Proper case-marks are usually a good indication of gold-content, but gold-testing is advised if you want to be sure. Markings on the case are sometimes ambiguous, and counterfeit or "upgraded" assay marks, while certainly not common, are known to exist. A good jeweler or goldsmith should be able to acid-test your case for gold-purity. Below are examples of markings on solid-gold watch cases.

Examples of solid gold case marks on American pocketwatch cases.  Left: Keystone gold case; Center: Solidarity gold case; Right: Crescent gold case.

Examples of solid gold case marks on American pocketwatch cases.

Left: Keystone gold case; Center: Solidarity gold case; Right: Courvoisier & Wilcox gold case. The Courvoisier & Wilcox trademark was "C. W. MFG. CO.", which should not be confused with the more common "C.W.C. Co" which was a trademark of the Crescent Watch Case Company.

Gold-Filled Watch Cases

James Boss, an early partner in the company that was to become the Keystone Watch Case Company, is credited with the development of the gold-filled watch case which was patented in 1859. Although James Boss certainly didn't invent the process of making rolled gold plate, Keystone "J. Boss" watch cases were the first widely adopted and commercially successful gold-filled watch cases, and are still commonly found on vintage watches today. If your Keystone case is marked "J. Boss" or "Jas. Boss" then it is a gold-filled case. After Keystone achieved success with gold-filled cases, many other case manufacturers began producing gold-filled cases.

Gold-filled cases were made by sandwiching together 2 bars of gold (typically about 1/2" thick) on either side of a bar of base-metal, usually brass or brass-alloy (typically 3/4" thick). The 3 bars were soldered together under high pressure and high temperature in specially constructed ovens. The composite 3-layer bar was then rolled through high-pressure rolling mills until the desired thickness was reached. The gold layers could consist of 10-karat, 14-karat or 18-karat gold. While this process produced a thicker layer of gold than electro-plating, the gold content was still no more than 5-10% of the total case weight. As such, gold-filled watches do not have any significant gold value.


"Guaranteed" and "Warranted" Cases

Gold-filled cases were often marked with a guarantee, another innovation credited to James Boss, which specified a number of years that the case was guaranteed to wear. A case that's marked "14K Warranted 20 Years" meant that the gold-filled case was made with a layer of 14K gold, and was guaranteed that the gold-layer would not wear through to the brass for a period of 20 years. If your case is marked "Warranted 20 Years" or "10 Year Guaranteed" or any other reference to a number of years or guarantee, then that is a sure indication that it is a gold-filled or gold-plated case. Note that the year-guarantee was related to the thickness of the gold layer, not to the karat-quality of the gold used in the gold layers. In general, a longer guarantee implied a thicker layer of gold. Most gold-filled cases were made with 10K or 14K gold.

The year-guarantee markings on cases continued until 1924, when the practice was prohibited by law due to the failure of some manufacturers to stand behind the so-called guarantees. If your watch case says "Guaranteed for x Years" you know that it was made prior to 1924. After 1924, gold-filled cases were simply marked "Gold-Filled" as seen below.

Example of gold-filled mark on Keystone “J. Boss” watch case.

Examples of Keystone gold-filled case marks. Left: Pre-1924 J. Boss case, scales indicate 10K gold. Center: Scales with crown indicate 14K gold. Right: Post-1924 J. Boss case, scales with crown indicate 14K gold.

Silver Watch Cases

Silver was also a commonly-used case material, and some beautiful examples of silver cases may still be found today. Silver cases can be marked in a variety of ways: Sterling (.925 fine), Coin Silver (around .90 fine, made from melted US coinage), Fine Silver (.995). Below are examples of coin-silver case marks.

Examples of coin-silver case marks on American pocketwatch cases. Coin-silver cases were made from melted US coinage.

Nickel Alloy Cases

In addition to gold and gold-filled cases, manufacturers produced cases from many other materials as well. Nickel-alloy cases look similar to silver, and were produced under many names by American case manufacturers. Each manufacturer had their own unique name, and their own formulation, but cases were usually a mixture of Nickel (45%), Copper (54%) and Manganese (1%).

Manufacturers often chose names for their nickel-alloy cases which were suggestive of silver content, but which actually contained no silver. Some common names for nickel-alloys and the companies that employed them are shown below:

Silverode Philadelphia Watch Case Co.
Argentine Bay State Watch Case Co.
Nickeloid, Silveroid Keystone Watch Case Co.
Nickel Silver Illinois Watch Case Co.
Silverine Dueber Watch Case Co.
Silverore, Oresilver, Silver Ore Fahys Watch Case Co
Silvaloy ??

Nickel-alloy cases were less expensive than silver and were very durable (much harder than silver), and many fine examples survive today.

Examples of "Nickel-Silver" case marks. These nickel-alloy cases with silver-ish sounding names actually contained no silver.

Base Metal Cases

Base-metal cases began to be produced in the 1920s, made from various silver-colored (white) or gold-colored (yellow) metals, and typically using a screw-back and bezel design. Base-metal cases are usually marked as such on the inside case-back or on the bottom of the center case ring.

Other Case Materials

There are examples of pocket watch cases made in platinum, rhodium or other "exotic" metals but these are quite rare. Many materials have been used to produce "one-of-a-kind" watch cases, but the materials listed above make up the vast majority of cases the collector is likely to encounter.