Tube style catch was patented in 1850.
Rarely found in a piece of jewelry, but it's good to know, aluminum was first displayed in 1852.
Celluloid was invented in 1868.
In 1894, screw back earrings were patented. Clip on style came later. The wire, some call fish hook style earrings have been around for a long time.
Jewelry marked with the letters R,G.P after a number (karat sign) represents "rolled gold plate." Very popular during the 1800 s and early 1900 s.
Sometimes G.F. will be found next to the karat sign and this represents "gold filled." Which is not filled with gold at all. It is actually plating and the layer of gold is usually thinner than the former. The marking might include a fraction before the karat sign. For example: 1/20 12 K. This means the plating is 12 Karat or 50% pure gold and 1/20 of the total weight is 12 K gold.
There is another marking that can be found stamped inside a piece of jewelry that also represents plating, H.G.E. The initials stand for hard gold electroplated. An electrical process was used during the plating of gold to this piece of jewelry.
In the late 1800 s, many pieces of jewelry were stamped "solid gold" or advertised as such, when the gold content was actually only 6 K or 10 K. In 1906, a law was passed that required the actual gold content be stamped on all jewelry. Before 1906, a lot of gold jewelry was not marked.
Pinchbeck is a very old metal made by mixing copper and zinc and looked a lot like gold. Christopher Pinchbeck (1670 - 1732) invented this gold look-a-like that wore well. The owners of real gold jewelry, during that time, had copies made in the metal to wear when traveling. They would leave their valuable possessions safe at home and avoid losing them to thieves along the way that prayed on travelers. The 1840 invention of the electro-gilding process as well as the legalization of 9K gold in the 1850 s, meant the use of pinchbeck was no longer needed. This type of metal is rarely seen today.
Hope you find this information useful. Next post contains similar info on silver and other metals.
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