When you bring your gold to a precious metals dealer for a valuation, the first question is: how is purity actually measured? For professional operators, the answer is XRF analysis — an advanced technology that can verify a metal's composition in seconds, without damaging it.
What X-ray fluorescence is
XRF stands for X-Ray Fluorescence. The principle is simple: the instrument directs a primary X-ray beam at the sample. The metal's atoms, excited by this energy, emit secondary X-rays of their own (the "fluorescence") at energies characteristic of each chemical element present.
By reading the spectrum of these secondary X-rays, the instrument identifies precisely which elements are present and in what proportions.
Why it is the best method
XRF analysis has clear advantages over traditional methods:
- Non-destructive: the item is not altered or damaged in any way
- Fast: results are ready in 15–30 seconds
- Accurate: composition measured to within 0.01%
- Transparent: the result appears on screen and can be shown to the customer
Traditional methods such as the touchstone or chemical assay (cupellation) are slower, less precise and — in the case of chemical assay — destructive.
The instrument we use
At Aurelia we use a Niton XL2 spectrometer, one of the most advanced and reliable portable instruments on the market. It is the same type of instrument used by refineries, mints and assay laboratories around the world.
The analysis is always carried out in front of the customer, in complete transparency. The result is shown on the instrument's screen and explained in detail.
What the analysis reveals
XRF analysis determines the sample's percentage composition. An 18-carat gold ring, for example, will show roughly 75% gold, with the remaining 25% made up of other metals (typically silver, copper and zinc). An investment bar will show a purity of 99.99%.
That information is the foundation for calculating an item's value against the official gold price per gram.