What Is Pure Silver?
Pure silver, also called as fine silver, has 99.9%. pure silver
What Is Sterling Silver?
Sterling silver is an alloy created when copper is added to pure silver in order to make the resulting compound more durable and less soft.
Usually, sterling silver has a purity of 92.5%, meaning that 7.5% of the alloy is made of copper or another metal (usually nickel or zinc).
There is also the so-called coin silver, which is an alloy of lower purity: It usually contains 90% or less silver.
Silver, Sterling Silver, and Tarnishing
Although sterling silver is more durable than pure silver, the additional metals in the alloy make sterling silver more prone to tarnishing.
This happens because the copper, nickel, zinc or other mixtures in sterling silver may react with oxygen and other elements in the air.
Sterling Silver and Plating
Often, sterling silver items are plated with a thin layer of pure silver to improve the shine of the piece.
Sometimes, however, you may see an item marketed as “sterling silver plated.” This often means that the piece is actually made of nickel, copper or another metal, not silver, and is simply plated with a layer of sterling silver, which will wear off after some time.
Recognizing Fine Silver and Sterling Silver Marks
Fine silver is stamped with marks such as 999, 99.9 or .999, indicating how much silver the piece contains per hundred or thousand parts.
Sterling silver made in the U.S. is marked 925, .925 or 92.5. Jewelry with lower purity is not considered sterling silver by U.S. standards.
It is worth noting that silver sold in Europe or other parts of the world may have purity lower than 92.5% and still be marketed as silver or sterling silver.
For example, German silver may have silver content as low as 80%. Russian silver may also have purity lower than 90%.
Because of the different silver content standards around the world, it always pays to inquire about the actual silver content of the jewelry you are about to buy and pay attention to the marks stamped on it.
Testing Silver for Purity
Silver is usually tested for purity using the so-called acid test: A small shaving is taken from the item and is put in acid to see if its color will change; if the acid’s color does change, this means that the piece has purity that is below 92.5%.
If you want to test the purity of your silver jewelry, you don’t need to do the acid test yourself – there are jewelers who can perform this service for you for a fee.
Remember: Before buying any jewelry advertised as silver or sterling silver, make sure to check it for stamped marks indicating the exact silver content of the piece