We usually recognize sterling silver by testing it with acid.

Many jewels are sold claiming to be sterling silver but are fake jewels, namely an economical 925 silver plated metal.

A popular method for testing silver jewelry is that of the touchstone.

Touchstone with acid used to test silver

Touchstone with acid used to test silver 

Free Bonus : Download our complete guide to silver jewelry (fr).

You'll discover everything you need to know to shop online or in store.

Testing silver with acid  

This technique consists in rubbing the jewel on a specific stone, called touchstone, which will very slightly file the jewel and keep a deposit of the superficial metal of the jewel.

We then deposit a drop of silver test acid on this metal deposit. The color taken by the emulsion of the acid on the metal gives us information on its composition.

The test acid emulsion on silver 925 is gray / whitish and darkens over time. When the acid is poured on a metal other than sterling silver, the emulsion turns immediately to black, green or other color depending on the metal.

This method is effective but useless in the case of a 925 silver plated fake jewel, since you'll test only the silver of the superficial layer of the jewel. Tested silver keeps a dull gray color that will disappear after a slight polishing or cleaning with wipe.

One method used in Mexico (see the video below) is to file the jewel in a hidden area when the jewel is worn, and to test silver under the filed area, then you know if your jewel is fake, plated silver or sterling silver.

 

In the video (fr) showing the acid test on silver jewelry, we see the clear difference in color taken by the acid emulsion in the case of a fake jewel.

Silver 800 or 925 : what is sterling silver ?

Sterling silver is a metal compound comprising at least 800 mass parts per 1000 of pure silver (also called silver 800/1000).

Silver is very ductile (malleable), it's necessary to add other metals to improve its mechanical properties, usually copper. Indeed, a jewel in 100% pure silver would deform at the least shock, pressure or mechanical stress.

american silver hallmarks

 Different American silver hallmarks 

The first pure silver title is 925 silver, commonly known as sterling silver. This is the one we find most frequently for silverware and jewelry.

We can also find massive silver at 950/1000, but it's rarer and mostly used by jewelers craftsmen of the Andes (Peru, Bolivia and Chile). The Peruvian jewels that we propose on the site are in silver 950/1000.

In France, a jewel in sterling silver must bear the seal of authenticity of the French state if it weighs more than 30 g. Few of your jewels weigh heavy enough to receive this stamp. But what about sterling silver jewelry of less than 30g, how to make sure of their quality ?

Recognize sterling silver with touchstone

professional-high-purity-graphite-stone-practical

There is an empirical method, called the touchstone, to test the silver of a jewel and determine the degree of purity.

It involves very lightly filing the jewel on the stone and testing the silver metal deposit with acid. We then do the same with pieces of silver of which we know the degree of purity, silver 800 or silver 950, and we compare the colors taken by the different acid emulsions on the tested silver.

This method is the oldest, fast and doesn't damage the jewel. You can visit this website to know more about products used for silver testing with touchstone.

I invite you to watch this video on how works a touchstone :

 

Free Bonus : Download our complete guide to silver jewelry (fr).

You'll discover everything you need to know to shop online or in store.

For further :

August 16, 2019 — Hugo Maherault

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