Mixing Metals. - post 270    Part 5 of a series on metals. 

                                                   

                                                    #4255 Vermeil bangle set with rubies.

Just how pure is your gold? Just how solid is your silver? 
For much antique jewelry, the answer is 'not at all'. There are lots of reasons why and lots of things we should understand and remember when considering the purity of a metal. 

For one thing, hundreds of years ago, there were no computerized systems nor fool-proof, sophisticated systems of quality control. **

How did they even get the gold to make jewelry? In many cases, a lady brought in a few pieces that were old and outdated and asked her jeweler to combine them into something entirely new. So, he melted Grandma's earrings; Grandpa's pocket watch and a few other trinkets and used the metal to create a gorgeous long gold chain. Now, when we test that gold chain, we might find that one link is 16k gold, another 18k gold and a 3rd 22k. 
Antique gold is not always homogenous. Expect differences in purity. 

Putting limited technology and historic biography aside, metals might not be pure for other, aesthetic and practical reasons.  

Aesthetics, price and durability are factors that go into mixing our metals. 

                                     

                                    #7272 gold-plated Georgian muff chain. 

Gold plating is a popular form of giving the appearance of gold.  Underneath that layer of gold cheaper metals will lurk. 
Creating the gold look with a bit of a cheat, has been in vogue for thousands of years. Mixing gold with mercury and then burning off the latter left not only a gold appearance, but eventually, a dead craftsman. That mercury was deadly poisonous. 
Technology advanced and gold plating using electronic methods were invented in the 1800's.  Gold is deposited in a thin layer over other metals using electroplating methods. The layer of gold might be microscopically thin and it might be reasonably, decently thick. Cost accordingly. Gold plating can confuse not just the eye, but some gold testing. We will talk about testing later. 

There is a variety of methods used to plate cheap metal with silver. This usually applies to domestic items and not antique jewelry, so we will discuss it on another occasion.

Meanwhile, a useful word to remember is 'vermeil'. Just a Frenchified way of saying silver with a gilt layer on top. This was and still is used in jewelry (like the ruby bangle above).

Plating is not restricted to gold over other metals. Even white gold is a teeny bit yellow. Modern jewelry lovers might want a more brilliant white look.  Rhodium plating diminishes the yellow tinge, adds strength to the jewelry and does not tarnish. It does eventually peel off and may need replating.   Similarly, the precious metal palladium is also used to increase the intense white appearance of gold. Since both rhodium and palladium are used in modern jewelry (post mid 20th century), they are outside the realm of our antique jewelry discussion. 

Gold-filled is not the same as gold-plated.  A lesser metal is bonded with some gold, legally 5% in the USA. The result looks a lot like gold. It is way more stable than plated metals and has become very popular today, since it is way more affordable, less likely to attract robbers and looks just as good. Even better, it doesn't change or fade over the decades and centuries.

#7578 Gold-filled child's bangle.

A very interesting development occurred in the early 1700's when Christopher Pinchbeck created an alloy using copper and zinc. The result looks a lot like gold and was commonly used in making Georgian jewelry. Unfortunately, the secret of his exact formula died with him and we no longer know how to produce the same gold-look-alike effect. 

                                                                                                                                                 

                                                                  #7677 diamonds set in silver over gold mount. 

Layering metals for other reasons:
Prior to electric light, it was agreed that diamonds show off better when set in white metals. Since silver tarnishes and oxidizes it was not suitable for the entire mount. Who wanted their beautiful dress or flawless skin ruined by black grubby marks? Therefore, it was the norm in previous centuries to place a layer of silver over the basic gold frame of a jewel. As platinum became more workable, it replaced silver over gold and even replaced the gold entirely.
When we look at many antique jewels, there is a clear and distinct layer of white metal over the underlying gold mount. 
Look for the clear layers of white over gold metal - a good way of proving that your jewelry is antique.

                                                            #6911    see layer of silver over layer of gold.                 

REMEMBER:
Plating might wear away. The thinner, the faster. You may be able to have the jewelry replated, but you might find yourself in an eternal cycle of plating and wear.

 

** this is the exact reason that hallmarks exist: a way of ensuring the metal was tested and found to be correct. It was also a way for the king to collect taxes, but that is a rabbit hole we will leave for another day.
    

Questions and comments: Please email antiques@brendaginsberg.com
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