How to recognize gold and know its fineness

Although gold is widely used in jewelry making, it is used in multiple forms. Your jewelry can be only gold plated (with a layer of 3 microns, see source), or made of goldsolid gold whose title can vary enormously. In France, gold is legally used for jewelry with a fineness ranging from 9 carats to 22 carats.

Here, a fragment of a gold coin and a gold ring whose gold titration we want to test

The pointsCons and classical methods of gold recognition

French law requires French jewelers to affix two specific marks to gold jewellery. The first mark is that of the craftsman who made the jewel (master’s mark deposited in customs), the second is the mark that establishes the fineness of the gold used. For further details on the legislation, consult the customs website relating to gold. If you don’t trust the brand or your jewelry doesn’t have any brand, there are other methods such as touch test and the electronic gold test.

Although the color of gold varies depending on the degree of purity and the alloys used, it differs in its density. Gold has a density of 19.3, almost double that of silver (density 10.5). The denser your jewelry appears to you, the more likely it is to be made of high-quality gold. There are other more or less reliable methods for testing gold which you can find here: tips for testing gold

While these methods may work for 22 or 18 karat gold grades, more reliable methods are needed to test 14 or 9 karat gold. The most common method so far is to touch test. THE the latest method is electronic gold test.

Which gold tester for the chosen test method.

These methods allow you to know the title of your jewelry.

Acid test for gold

This is the method used by most jewelers because it is quick and non-destructive to the jewelry. It consists of marking a touchstone with the jewel to be tested and then testing the trace of gold on the stone with different acids. You will easily find gold testing kits on the web: on this site.

This video summarizes the testing process very well:

Electronic gold test

This technique is even easier thanks to the Mizar M24 device that I found here. It allows you to test yellow, white, green and red gold with grades ranging from 9 to 24 carats.

The principle is to test your jewelry by circulating a current through it. The test lasts only a few seconds and allows you to know with good precision the gold content of your jewels.

You can see the testing of a 22 karat gold coin and 18 karat gold wire in this video:

This test method covers all scenarios. Most acid kits do not test all gold grades, i.e. 16K, 20, or 22K gold.

To go further: