and other white metals
How to test platinum, white gold, palladium, steel and silver
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In 2012 several jewellers bought white metal they thought was 18ct gold, it turned out to be steel, they had acid testing sets but weren't sure how to test for white metals. In one case the catch to a bracelet was made of 18ct white gold and was marked as such, but the remainder of the bracelet was steel.
In 2015 I was taking a training course for the managers of a chain of shops, they showed me a collection of white metal bracelets several stores had bought, paying between £500.00 and £700.00 each. They were steel. The managers explained that their shop staff knew nothing about gold and had to rely entirely on the acid test. That's fine, the acid test works well, but I also do recommend that anyone who buys scrap learns a little about the characteristics of gold and silver!
This article has some tips about how to detect steel without the need for acids, and how to test for steel, platinum, white gold and palladium using acids. You must use the 18ct (blue) acid and Platinum (green acid) and a strip of test paper, you cannot use the 18ct (blue) bottle or the 'Platinum' (green) bottle on their own. Although there's a summary below, please read the instructions that came with your testing kit.
Firstly, the marks. If an item is simply stamped with a number, and nothing else, it is 'marked' - but that mark is not a hallmark, it means nothing, you have to test the item. Anyone buying or selling precious metals must, by law, display a hallmark chart. Get a chart, learn to recognize the marks, a hallmark is your guarantee that the item is genuine. A hallmarked tab (or catch or link) fixed to a 'base' metal item is considered a serious fraud and the Assay Office and the police will be very keen to investigate. Hallmarks are controlled by the government, a forged hallmark is considered the same as a forged banknote, they are very rare but they exist. Experienced jewellers recognise cheap costume jewellery posing as platinum, they can see, instantly, that it's a fraud; they recognise handmade diamond jewellery and would never question the mark, they know it's platinum; but if you are new to the trade you may wish to start by testing everything.
START WITH THE EASIEST TESTS
Testing white metals really is simple.
Before carrying out an acid test, you must file the item to get beneath any surface plating (don't be shy, be firm, you may be filing through gold plating then copper then steel):
Testing yellow metals is easy, follow the instructions that came with your acids (e.g. a Quicktest 3). This article is about how to test white metals.
Start with the obvious, test it for silver, especially if the surface is gold colour and the underneath is white. The Quicktest SILVER acid (the 'AMBER' acid) turns red on silver. Take care to test only the filed area, if the acid touches both the filed and a silver plated area, the entire spot of acid will turn red. If it is not silver, the spot of acid will remain amber. Only silver makes the acid turn red, it will not turn red on white gold, platinum, palladium, rhodium, steel, chrome or nickel. For those that are colour blind: red is the really deep tone, amber is a clear transluscent-golden tone. Please read the instructions that came with your set of acids, especially the safety precautions.
Now you have tried the obvious, move on to the gold acids - this is how you test white metals:
Always start with the Quicktest 9ct acid (the 'WHITE' acid), apply it to the article as described in the instructions that came with the testing set, if it fizzes it is not gold or platinum. If it stays clear, move onto the Quicktest 14-24ct acid (the 'BLUE' acid). Please read the instructions that came with your set of acids, especially the safety precautions.
The 14-24ct/blue acid gives really clear easy-to-see reactions on yellow gold, even for the colour blind (I recommend the Quicktest-3); testing white gold takes just a little more care. Apply the 14-24ct/blue acid to the article as described in the instructions that came with the testing set:
The advanced test uses the 'platinum' bottle (the 'GREEN' acid) from the Troytest set.
Place the blue acid on the item, allow plenty of time for any colour change, soak up the spot of acid with a strip of test paper (see the Troytest sets, also replacement books of test papers) then put a spot of the green acid onto the stain on the paper.
I shall repeat the above paragraph in special language for the colour blind (a significan percentage of the populatiion is red-green colour blind):
14ct to 18ct = light stain on paper and turns dark when you put a drop of GREEN acid onto the stain.
Steel = light stain on paper and bleaches out (goes clear) when you put a drop of GREEN acid onto the stain.
Palladium = dark stain on paper and ...turns darker when you put a drop of GREEN acid onto the stain.
Platinum = no colour, it just looks 'wet', as you would expect if you soaked up water.
Platinum is the easiest metal to test, you can leave the blue acid on the metal for several seconds, or even for a minute, and nothing happens at all, it looks just like water; then soak up the spot of acid with the test paper and nothing happens, it looks just like water; then apply the green acid to the stain and nothing happens, it looks just like water.
It is important to note that the above instructions are for those who already use acids and know how to handle them, PLEASE do not buy loose bottles of acid unless you already have a secure (preferably lockable) box and the full instructions and (most important of all) the acid safety instructions.
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