Identifying Precious Metals: gold, silver and platinum

As precious metals can have high monetary value, this is an area where getting a educated second opinion can be a good idea for a beginner. A jeweler or avid collector can identify and grade the metal for you. However, the avid collector can make a fair judgment about type and quality of previous metal.

There are both scientific tests and more informal ways of identifying gold, silver and platinum. The first part of this post looks at the quick-and-dirty, unofficial in the antique store methods, methods. The second part of the chapter will show the scientific acids tests.

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Informal quick tips for identifying gold, silver and platinum 

* Look at different metals to get an eye for the look. Though somewhat similar in color, gold looks different than brass and copper. Silver looks different than pewter and aluminum. An experienced eye is helpful.

Gold

* Gold is a shiny yellow color and does not corrode or rust. Very old gold can look shiny brand new. Gold is both very soft and heavy.

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an ancient gold coin can still by bright and shiny

* Gold is not attracted to a magnet. This is not a definitive test as some other metals are also not magnetic.

* Many people do the simple test of running gold along unglued porcelain tile. If the mark that is left is yellowish-gold the metal is real. If the mark is black the item is not.

* Gold is usually that yellow gold, but it can come in different tint or color variations depending on the allow. This includes white gold which almost resembles silver or platinum.

* Is 2.5 -3 on the mohs hardness scale

Silver

* Silver is, well, silvery colored. It looks slightly different than steel, though steel kitchen utensils are often mistaken for steel.

*Silver is not magnetic. Some but not all steel is magnetic. A refrigerator magnet is excellent at identifying many steel kitchen utensils and bowls.

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Silver has a naturally dull finish. Only silver-plated is shiny. Steel is often shiny. 

tarnished silver

tarnished silver

* Steel is colder than silver. Touch it to the side of your face. 



* Rub a clean, white polishing cloth over a silver piece. Real silver and silver plate will turn the cloth black.

* Is 2.5-3 on the mohs hardness scale. This is soft. Softer than steel and glass.

Platinum

* Platinum doesn’t tarnish or degrade, including very old pieces.

* Platinum is the heaviest precious metal, noticeable heavier even than gold.

* Platinum is not attracted to a magnet. Some but not all steel is.

* Is 4-4.5 on the mohs hardness scale

*** Hallmarks

Precious metals often have hallmarks on them, identifying the type of metal, percentage of precious metal (14kt, 24kt, etc), era and where graded. As this is a full topic in and of itself, it will be discussed in a later post. Also, hallmarks can be forged so you can’t rely just on them.

*** Precious metals acid testing kit

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acid test kit with clearly labeled bottls

There is an inexpensive and use to use kit to testing precious metals that use acids to test the metals. These kits can be bought at amazon, ebay and other places. The kit includes the testing acids in little eye drop bottles, a testing stone and instructions. You don’t have to be a chemistry expert or have lab experience to do the tests. Be careful with the acids as they can stain or worse your hands, and keep it away from your eyes.

Testing Gold with the acid kid:

There are clearly labeled bottles of 9kt, 14kt, 18kt and 22k testing acids in the kit.
The process is simple, scratch or rub the metal in an inconspicuous area onto the testing stone so there is a little streak of metal. 
Place a drop of the closest acid to the karat you estimate the metal to be.

If the acid dissolves the metal it’s less then the karats on the bottle and you should try again with lower level acid.

If it dissolves the metal slowly, it’s possible you would have a bit less then the karat of the acid in the bottle.

If the metal stays it’s most likely the karat of the acid in the bottle.

 

Platinum

Should stay and not dissolve under the platinum acid.

 

Silver:

Make a ittle metal streak on the stone, apply a drop of the acid and white fa bit or a color to appear.

0.999 pure silver will turn bright red color

0.925 sterling silver will turn dark red color

0.800 silver will turn brown color

0.500 silver will turn green

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