Measuring the Purity: 5 things to keep in mind when testing precious metals

Metals which are commonly utilized in the metalsmith’s studio are the coloured and white metals. The coloured metals include copper, pure gold, gold alloys, and the non-precious alloys such as bronze and brass. The white metal category includes options such as pure silver, white gold, silver alloys, platinum, and platinum alloys. There are also white non-precious metals such as lead, tin, cadmium, and the alloys of these metals. Through metal testing, you can easily determine if a particular sample is a base or a precious metal, and what fraction of a particular alloy is precious. Sophisticated equipment such as the XRF analyzers is crucial in determining the content as well as the purity values of metals with great precision. When it comes to testing precious metals, there are a number of things you need to keep in mind:

  1. Prepare the Space for Your Test

Since some tests are usually corrosive in nature, you’ll want to make sure your area is well-prepared for testing. A slab of marble, a piece of Formica, or a glass of baking pan that is covered with a paper towel can be an excellent surface to work on, especially when corrosive substances are used. Make sure these items are clearly marked so you don’t accidentally use them as food items in the future. Also, ensure there is a bottle of water with some baking as a precautionary measure should an emergency arise where acid neutralization is required. Being cautious about any metal testing procedure is necessary for safety reasons.

  1. Consider Visual Inspection

Just like the case of jewellery analysis, visual inspection is an effective technique when it comes to precious metal testing. With a magnifier or a 10x loupe, you can examine a piece of metal to determine if a particular metal is authentic or not. In any area of collectable, antiques, and precious metals, there are fakes for both the old and new. For jewellery, you can use the loupe to search for evidence if the item is not silver or gold. Look for sections that are highly likely to wear: the bracelet clasps, the chain joints, and the pendant’s back surface. If there are signs of brass or copper, then you’ll know that your item isn’t made of silver or gold, and in that case, no more testing is necessary. However, if your visual inspection reveals even tone and colour to the surface of your piece without signs of plate loss, then you can proceed with further testing.

  1. Acid and Scratch Test Require Extreme Care

A good number of jewellery professionals utilize the “Acid Test” to analyze the fineness of metal. Kits used to test precious metals can be acquired from various jewellery stores either physically or online. A basic kit of this kind comprises a wooden box that contains three bottles of acid for testing 18kt, 14kt, and 10kt gold. If you buy your testing kit by mail or any other means online, you’ll need to get nitric acid from the local chemical supply for your testing solutions to be complete. Included in this kit should be a set of test needles and a black basalt touchstone. The needles are metal tapers which are tipped with 18, 14, and 10 karat gold. You should also note that needles with a broader karat range are available.

In case you have never carried out a scratch test before, you can start by practising on surfaces which aren’t made of precious materials. If not done carefully, scratch testing can be destructive, so go for items with little or no value to practice your skills. Additionally, do not forget to exercise extreme care when handling silver and gold testing solutions, as these are often very corrosive. If the solution comes into contact with your skin, flush with plenty of water and baking soda or sodium bicarbonate. In case the solution is swallowed, seek medical attention immediately. As with any substance containing caustic chemicals, make sure your test kits are kept away from children’s reach.

  1. The XRF Analyzer is one of the Most Accurate technique to Use

Apart from visual inspection and acid tests, the use of an XRF analyzer is one of the most accurate and effective techniques when it comes to precious metal testing. With the high price of silver, gold, and other precious metals, it is essential to take all the necessary precautions to ensure that the testing procedure used is accurate and dependable. Reliable and accurate test results remove subjectivity and variability in measuring the authenticity of precious metal while at the same time ensuring a fair transaction. Today, many businesses depend on the XRF analyzers for nondestructive, fast, and accurate precious metal analysis. These gadgets provide the percentage of elements as well as the exact karats in an item, thereby identifying the non-standard and counterfeit metals.

  1. Any Magnetic Object Isn’t a Precious Metal

Another technique you need to know about when it comes to testing precious metal is the use of neodymium magnet. Gold and silver, being two of the most common precious metals are usually non-magnetic. With this knowledge in mind, when testing for silver or gold, use the neodymium magnet to run over the metals in question to determine their authenticity. If you detect a magnetic pull, there is a high chance that the items are not a precious metal, although a small magnetic piece could imply the presence of a magnetic alloy or even a plating. Despite that, when testing for the purity of precious metal, disregard anything that appears to be magnetic unless you are certain it only the base metal. You should also remember that jewellery clasps have magnetic springs and earing may have magnetic posts, so you need to consider this aspect so as not to disregard the entire piece.

Final Word

When it comes to testing for the authenticity of precious metals, it is important to consider the pointers highlighted above. Having the right supplies for your tests is necessary if you are to get accurate results from either of the processes above. It is also recommended to combine two or more of the above techniques so you can be confident about the outcome of your tests.



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