We’re thrilled you’ve chosen a unique piece from our store! Along with your jewelry, you’ll find an XRF (X-ray fluorescence) analysis report. Here’s what it means and why it matters.

XRF stands for X-ray fluorescence, a scientific method used to determine the exact metal composition of an item — quickly, safely, and without damage.

• A beam of X-rays is directed at the jewelry.
• Each element in the metal gives off a unique “signature” of energy.

The XRF device reads these signatures and calculates the percentage of each metal present.

Sometimes metals look like gold but are not gold, or can be a less expensive metal covered in a layer of gold as thin as a couple micrometers.  These can be very difficult to identify even for experienced jewelers.  One of the best ways of testing metals without melting it is with the XRF technology.

At Sterling Style Shop we use the XRF as part of a multi layer strategy to make sure customers are getting what they expect.  We provide this information to you so that you can rest assured your jewelry has been hand curated, tested, and you are getting what .

Each row in your XRF report shows three key pieces of information:

1. Element Symbol – The chemical symbol for the element detected (e.g., Au = Gold, Ag = Silver, Cu = Copper). See the included table for a quick guide to commonly found elements in jewelry alloys.
2. Percentage (%) – The proportion of that element in the tested area. This is the critical number for confirming whether a piece contains the expected amount of precious metal based on the stated karat or purity.
3. Precision (±2σ) – This number shows how much the result might vary if the same spot were tested repeatedly. It is expressed directly as a percentage. For example, if gold is reported as 75.0% with a precision of ±0.5%, that means 95% of repeat tests of the same spot would fall between 74.5% and 75.5%. A precision value of ±0.5% or less is considered very consistent for jewelry testing.

The percentage you see on your XRF results will depend on the anticipated purity of the jewelry. Here are two reference charts for common gold and silver purity levels:

To better understand how to interpret your XRF results, let’s take a closer look at an example report.

In this report from an 18K necklace, we see the gold content is measured at 75.419% Au. The precision value (±0.395%) means that if you were to test this same spot again, 95% of the time the result would fall between ~75.0% and 75.8% Au. This shows the reading is very consistent. Remember we're looking for less than or equal to .5 in this column.

Next, you can see that silver (Ag) makes up 12.088% of the metal, and copper (Cu) makes up 12.156%. These other elements are normal parts of the alloy that give the jewelry its color, hardness, and durability.

Finally, you might see other elements that show up in tiny quantities, these are either trace elements in the metal or background noise from the testing environment.

An 18K piece is defined as containing 75% pure gold, but in practice the exact percentage can vary slightly. Modern alloys are usually very close to that mark, while antique jewelry may show small variations because of historical refining and casting methods, or later repairs using solder. On an XRF report, it’s normal to see results for 18K jewelry anywhere in the range of about 74% to 76% gold. Readings within that window are consistent with genuine 18K.

Here's a table of elements that commonly appear in jewelry: