Frequently Asked Questions | Goldanalytix

Here you find answers to the most frequently asked questions on all topics related to precious metal testing. The questions and answers are neatly arranged according to key topics - so you can find what you are looking for very quickly.

Jewellery inspection

How can I determine the alloys of jewellry?

The best way to find out the composition of jewellery alloys is to use test acids or an XRF instrument. With the test acids it is possible to find out the carat content of jewellery, as well as some other components of the alloy. When analysing with an X-ray fluorescence device, it is even possible to determine the exact qualitative and quantitative composition of the alloy. For private customers, these devices are usually not profitable with prices of 20,000 € upwards.

What types of fake jewellery exist?

For jewellery, there are two main types of counterfeiting. One common form of jewellery counterfeiting is false hallmarks, i.e. sub-alloys in which a higher proportion of gold is stamped on than is actually present. Test acids or density scales can protect against this. The other form is the use of counterfeit materials, such as wolfram carbide jewellery with gold plating, or e.g. "Autobahngold", which often consists of gold-plated brass or stainless steel. Here, the GoldScreenPen is the testing device of choice.

Is the magnetic scale suitable for jewellery?

For jewellery, there are many different alloys with a wide variety of metals. Since the magnetic scale measures very finely, even a small proportion of a ferro- or diamagnetic metal (e.g. nickel, platinum) can influence the result, making it no longer meaningful. Therefore, the magnetic balance is not suited for jewellery testing.

What does the carat number on my gold stand for?

For diamonds/gemstones, carat is a measure of weight. Here, one carat corresponds exactly to 0.2 grammes.
In the noble metal trade, on the other hand, the gold content of bars and coins is indicated as the fineness or fine gold content, usually in the form of an embossing. Pure gold bars are stamped 999.9, also known as "four nine fine".
Below you will find an overview of the carat specifications for gold:

8 Karat:
Gold 33,3 %

9 Karat:    
Gold 37,5 %

10 Karat:
Gold 41,7 %

14 Karat:
Gold 58,5 %

18 Karat:
Gold 75 %

20 Karat:
Gold 83,3 %

21 Karat:
Gold 87,5 %

22 Karat:
Gold 91,666 %

24 Karat:
Gold 99,9 %

Does the GoldScreenPen indicate the carat number?

No. The GoldScreenPen measures the conductivity (like the GoldScreenBox) and is therefore ideal for counterfeit detection. Sub-alloys or the exact carat number cannot be measured with a carat number smaller than 21, because the conductance values ​​of these alloys only decrease very slightly with decreasing gold content.

Currently, the test acids or the density scale are the best methods to determine the carat number.

A device that fulfills exactly this function is currently under development and is expected around the end of 2021.

Is jewellery testing different from testing bars or coins?

Bars or coins are usually made of pure gold or known alloys. For precious metal jewellery, however, there are many different compositions of the most diverse materials, which can be challenging task. If you want to know in detail what to look for in jewellery testing, you can take a close look at our gold test page.

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