gold purity check, gold is real or fake, how will you easily check the purity of gold? Understand from expert – gold purity check is the gold you are buying pure here are how to check purity says expert

Sydney: When it comes to gold jewellery, the question that arises is how pure is it? And how would one know its purity? Recent revelations about Australia’s official bullion mint and Western Australia-owned Perth Mint show that gold buyers and sellers take purity very seriously. Questions have been raised about the impurity in nearly $9 billion worth of gold sold to the Shanghai Gold Exchange. The question of how to test the purity of gold has been around for thousands of years and increasingly new methods have been invented to find out its purity. But despite these practices, the gold industry still runs on trust and reputation.

It is said that the ancient Greek mathematician Archimedes invented a way to test the purity of gold while taking a bath. The story goes that the king of Syracuse asked a mathematician to find out whether a crown of gold was made of pure metal or had been adulterated by unscrupulous goldsmiths. While considering the problem, Archimedes took a bath and observed that when he immersed himself in water, the water level rose. He immediately got out and ran down the street shouting ‘Eureka’ (or I’ve got it). They felt that by immersing the crown in water, they would know its volume and density. Since gold has a higher density than most other metals, it can be used to measure the purity of a crown. However, the historical veracity of this story is debated.

fire and light
Despite the simplicity of Archimedes’ method, it is not used today. Some methods used in the modern gold industry include fire assay, X-ray fluorescence, and plasma mass spectrometry (ICP-MS). The fire assay is a traditional method used in the hallmarking industry (for example to verify whether the gold in jewelery is nine karat or 18 karat) and used in gold mines to test the quality of ore. In this, a small sample of the metal of the substance you are examining is taken and mixed with various chemicals and melted in a furnace. However, the fire assay only tests for the amount of gold, not what else is in the sample. Another common test is X-ray fluorescence. You X-ray the material you want to investigate, which excites the atoms in your sample and turns them into X-rays of different wavelengths. With this machine, you get to know the amount of gold, silver, copper and other metals in that substance.

gold standard
There are several different, more detailed checks you can do to gain accuracy. In Australia the “gold standard” refers to plasma mass spectrometry. In this process a sample is effectively vaporized and then the various atoms in it are weighed. However, it is a bit expensive process. You wouldn’t use it for jewellery. It is mainly used by scientists or mining companies to detect adulterants in a sample.

Cost of trust: Practically people do not do these tests while buying gold. The gold industry largely runs on trust. If a reputed seller tells you that they are offering you 99.99 percent pure gold, you usually believe them. You don’t check every coin or brick of gold. For whatever reason, the Shanghai Gold Exchange did not believe the Perth Mint’s assurances about the purity of the gold supplied to it. Now this may be a credibility problem for the Perth Mint. And when trust is broken, it is not easily rebuilt.

(Michael Courte, Physics Discipline Leader, University of Technology Sydney)