GOLD JEWELRY ANALYSIS: XRF APPLICATIONS
Determining the purity of gold is a major challenge faced by the gold industry today especially when tungsten element is involved. This is because the density of the gold or the scientific value of the aurum (Au) is almost the same as the density of tungsten (W). Therefore, various methods have been introduced to distinguish between natural or artificial gold. There are two techniques to test the purity of gold, namely, destructive and non-destructive techniques. In this article, the non-destructive technique will be further explained as it retains the original physical shape of the jewelry without destroying it. Jewelry fans or customers prefer this type of technique because their jewelry is still preserved and can be styled as often as possible without flaws that may be present during the test. Some of the most commonly used techniques are densitometers, ultrasound and X-ray fluorescent (XRF). Furthermore, the XRF technique provides a more comprehensive, easy-to-use, fast-paced analysis solution and requires no harmful chemicals. However, XRF can only test on the surface of the jewelry up to 2 mm in depth (depending on the capabilities of the equipment). At Malaysian Nuclear Agency, the determination of the gold standard is done using XRF technique. Standard samples of 999 gold, 950 gold, 916 gold, 835 gold and 750 gold were used as measuring standards to determine the purity of gold. In addition to the percentage, gold can also be categorized as karat. Using this technique as well, the determination of the purity of gold can also be carried out at any desired point or area. Moreover, the gold thickness can also be measured by performing a surface thickness profile.