Gold Testing

Acid testing is probably the most widely used of all the gold testing methods. A selection of different Karat acids are formulated to react in different ways when they come into contact with genuine gold items of a certain Karat. This method of testing is done by placing a small drop of acid onto the surface of the item, sometimes it is required that you scratch the test surface in an inconspicuous place to be sure your not testing a gold plated item, this can be done with a pocket knife or small file. By breaking the surface of the metal the acid will give a more accurate result. Place a small drop of acid directly on the scratch starting with the lowest Karat acid first e.g.9kt. Observe the reaction and compare to a colour reference chart that is usually included, repeat the test with a higher value Karat acid if necessary until a colour match is found. Genuine or solid gold will usually leave a brown stain and non gold items will leave a green stain on the metal or react by bubbling and sizzling indicating that the item is either gold plated or contains copper as a base metal. Rinse the test item in clean water to remove any excess test fluid, any light staining left behind can be easily removed with a pencil eraser or buffing wheel. Always exercise caution when using Acid Testing Kits and be sure to read all safety information provided with your kit, acid is very corrosive and toxic.

Electronic gold testers

The electronic gold tester is a relatively new addition for the scrap gold dealers toolbox, briefly it consists of an electronic circuit and a test plate of reference gold all housed in a neat desktop size box. Gold is tested by applying the test solution (acid) onto the test plate then immersing the test item into the testing solution being careful not to make contact with the test plate. How this works is the test item forms part of the electronic circuit by connecting a crocodile clip, when the item makes contact with the test solution the circuit is completed and a small amount of the test item is dissolved and analyzed by the gold reference test plate, very clever stuff as it only requires a single bottle of testing acid to test a wide range of Karatage from 9kt all the way up to 24kt . Test solution has to be cleaned up and replenished for every new test performed. It may be necessary to file or scratch the test item if heavy gold plate is suspected but generally pretty reliable and capable of detecting most gold plate items no problem.

Touchstone Gold Testing

Touchstone testing involves rubbing your test item of gold onto a Touchstone, this is usually a ground sheet of lightly textured black glass, fieldstone or slate. This method still requires the use of acids and you will also need a selection of genuine known gold samples to compare your test results. The acid solutions used are marked for different Karat's of gold as a reference point. Rub your test item against the touchstone so as to leave a mark or small deposit of gold on the surface of the touch stone then do the same with a known gold item, apply a small drop of the test acid to each mark and observe - compare the reaction of the acid and repeat the test with a different Karat acid until a match is observed. Remember to test a fresh portion of the mark as you don't wont to cross contaminate the test acids. This method is best suited for known items of gold that are not hallmarked and you just really need to determine the Karat or purity of the gold.