Use of X-Ray in Non Destructive Testing to determine gold karat

Abstract

The fire assay technique is the oldest and most reliable method used to determine gold karat, because of the destruction of gold into pieces and the long time which spent at analyzing; a well powerful for nondestructive analytical analyzer had took it place, it is x-ray fluorescence spectroscopy (XRF) that we used to analysis gold specimens. It is fast and accuracy technique, XRF can provide qualitative and quantitative analysis regarding the thickness of the tested material by measuring the intensity and characteristic energy of the emitted x-rays. The present work explained the analyzing of eleven specimens of gold bullions and jewelry at XRF laboratory in Sudanese standard and metrology organization (SSMO). As a result of x-ray fluorescence analysis; only three alloys were observed in XRF spectrum of all gold samples, gold metal, silver and copper metal with different ratios which calculated by stocks instead of gram, a pure gold piece 24 karat includes 1000 stocks of gold, also three different gold karats were determined jewelry testing: 21 gold karat which contain about 875 stock of gold, 18 gold karat has 750 stock of gold, 14 gold karat has 580 stock. Alloys values were recorded for all specimens.