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.

Top 5 questions

Which gold tester is best for me?

That depends on the objects you want to analyse:

For classic investments (coins and bars), the GoldScreenSensor in combination with a caliper and precision scale is usually sufficient (also measures through packaging). For bars from 50 grams and upwards, we recommend the BarScreenSensor, for which the objects have to be unpacked.

For jewellery, the CaratScreenPen is the best way to measure the carat number of gold objects. Another way of testing jewlery is with a combination of the GoldScreenPen, the density scale and a test acid set. The GoldScreenPen can also be used for smaller investment objects up to approx. 1 ounce.

As a tungsten detector, the MagneticScreenScale is a alternative to the GoldScreenSensor for gold objects from about 1/4 ounce up to 250 g. For those who want to focus entirely on gold and do not intend to unpack 100-gram bars, for example, the MagneticScreenScale is a good choice.

For larger or irregularly shaped bars whose dimensions cannot be determined with sufficient accuracy with a caliper, the bar testing set is recommended.

What are the characteristics of a reputable dealer?

Memberships and certifications:

Official gold dealers usually have memberships such as with the "Berufsverband des Deutschen Münzenfachhandels e.V." or a "Good Delivery" certification from the "London Bullion Market Association". Members and certifications of this kind can be viewed publicly on the respective sites.

"Spot Price":

Dealers are tied to the current price of gold, the spot price and do not sell below value. If you find a particularly cheap offer on the Internet, you'd better watch out.

Service Tests:

Credible gold dealers can also be found in service tests. Test series by "Focus Money" or "Euro am Sonntag" regularly review various providers, which you can use as a guide.

Homepage and communication:

You can already unmask scammers on their homepage. Compare the prices of the offers with the current gold chart.

Personal contact with the dealer:

Reputable dealers always offer you personal contact as well and can be reached by phone at any time.

Product Description:

Here you can also immediately recognize bad counterfeits. Reputable gold dealers usually offer you high-resolution pictures of the products, while counterfeiters usually offer inferior ones to disguise obvious external differences. "Gold plated" does not mean solid gold, "fine gold plating" is nothing more than foreign metals covered with a thin layer of precious fine gold. You should also interpret expressions such as "replica", "medal", "replica" or even "counterfeit" as warnings.

What precious metals are worth buying?

Precious metals always offer investors a kind of security during crises. More common metals such as gold and silver can thus also be used as a medium of exchange, but more unknown precious metals are associated with a risk for precisely this reason. The respective prices are usually very dependent on the market and can fluctuate greatly depending on events. Safe investments are gold, silver, platinum and palladium.

Gold has the chemical symbol Au (Aurum). Although gold is also used in medicine, for example, it is traded less as a raw material and more as a pure investment metal.

Data on Gold 999:
Colour: yellow, gold
Density: 19.3 g/cm3
Conductivity: 45 MS/m

Silver has the chemical symbol Ag (Argentum). The precious metal is extracted from silver, copper and lead ores. Unlike gold, silver is traded on the stock exchange as a raw material, which is also needed in industry. Small investors can buy silver in the form of up to five kilo bars and coins.

Data on Silver 999:
Colour: shiny greyish, silver
Density: 10.5 g/cm3
Conductivity: 61 MS/m

Platinum has the chemical symbol Pt. It is one of the most valuable precious metals of all, as it occurs in much smaller quantities than gold, for example. Due to its corrosion resistance, it is used in medicine as well as in industry. Platinum is traded in the form of bars and coins.

Data on Platinum 999.5:
Colour: greyish, silver
Density: 21.45 g/cm3
Conductivity: 9.1 MS/m

Palladium has the chemical symbol Pd. It belongs to the platinum metals, which makes it valuable. Palladium occurs in combination with copper, nickel, gold and silver ores. It is mainly used in dental technology. It is also traded in the physical form of bars or coins and can be acquired by small investors as an investment.

Data on Palladium 999.5:
Colour: greyish, silver
Density: 11.99 g/cm3
Conductivity: 9.2 MS/m

Copper has the chemical symbol Cu. It belongs to the group of coinage metals. It is also very conductive and easy to process. It is mainly found in the automotive and mechanical engineering industries, but now also in renewable energies. For investors, it can be bought in the form of bars as well as coins.

Data on Copper 999:
Colour: reddish brown, metallic, copper-coloured
Density: 8.92 g/cm3
Conductivity: 58.1 MS/m

Rhodium has the chemical symbol Rh and belongs to the platinum metals. It occurs very rarely in nature, which is why it is extremely expensive. Consequently, its use is not common, but rhodium is found mainly in automotive catalytic converters. Investment rhodium is also available in the form of ingots.

Data on Rhodium 999:
Colour: silvery white, metallic
Density: 12.38 g/cm3
Conductivity: 18.5 MS/m

Iridium has the chemical symbol Ir and is the second most dense element after osmium. It is one of the rarest, non-radioactive metals of all. Iridium is mainly used in mechanical engineering and medicine. The Urkilo, which is kept in Paris, and the Urmeter, which is also located there, are also made of an iridium alloy. The precious metal is very valuable and is traded on the stock exchange. Iridium bars and coins are also available for small investors.

Data on Iridium 999.5:
Colour: greyish, matt silver
Density: 22.56 g/cm3
Conductivity: approx. 19.7 MS/m

Ruthenium has the chemical symbol Ru and belongs to the platinum metals. It is very rare and is only used in small quantities. Main applications of the metal are in the electronics industry. Some complexes of the metal are being researched for their effect as an anti-cancer agent. For investors, ruthenium can be purchased in ingot form.

Data on Ruthenium 999:
Colour: silvery white metallic
Density: 12.37 g/cm3
Conductivity: 14.1 MS/m

Can a counterfeit or a counterfeit alloy give a positive result? (MagneticScreenScale)

Under certain circumstances, a counterfeit can produce a positive, i.e. diamagnetic, result on the magnetic balance if the foreign core is hidden too deep inside and thus the paramagnetic "false core" is not detected by the diamagnetic layer. The maximum thickness of a gold layer through which measurements can be taken by the MagneticScreenScale is approximately 2.5 mm.

Likewise, a coating made of a strongly diamagnetic material that produces a strong positive value (e.g. bismuth) can, so to speak, compensate for the paramagnetic core lying further inside (which produces a negative value) and then falsify the value in the direction of "+". However, such forgeries would be difficult to produce and would require a relatively thick layer, e.g. bismuth, and would therefore be conspicuous in the weight or density test.

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 precious 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. The CaratScreenPen measures the carat number of gold within seconds. 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 %



New questions

What should I consider when purchasing gold?

Anonymous purchase only possible below 2000 Euros:

If the purchase of gold, silver or other precious metals in Germany is to remain anonymous, the price of the purchased precious metal must not exceed a price of 1.999.99 Euros. For any sum exceeding this amount, the dealer is required by the Money Laundering Act to record personal details. Most countries have their own limitations, which should be researched before buying.

For large gold bars, the dealer surcharge is lower:

If a fixed amount is to be invested in physical precious metals, it is advisable to buy bars that are as large as possible, as the dealer's markup is comparatively large for small bars. A 1-ounce bar costs about € 1770 (as of August 2023). 1 ounce of gold in the form of 1 - gram bars, on the other hand, costs 1840 Euros. The price per gram exceeds the price of an ounce significantly. For coins, the premiums are also higher than for bars because of the minting.

Buy gold coins or 995 gold bars instead of paying VAT:

In Germany, if gold is to be purchased in bar form, it makes sense to buy pure gold bars (99.5% gold content), as no VAT is due for this purity or more. Gold coins are exempt from VAT from a purity of 90% on, but only if they were minted after 1800 and are or were considered official currency in their country of origin. In addition, the price may not exceed the material value of the gold content by more than 80% (some collector coins have an even higher market value). When buying silver or other precious metals from commercial dealers, the usual 19% German VAT is always charged in Germany.

Jewellery and collector coins are mainly suitable for connoisseurs:

With jewellery and collector coins made of precious metals (e.g. antique or rare coins), it should be noted that the value of the piece is not only composed of the pure metal price, but other factors can also influence the value. For jewellery, for example, the quality of workmanship, the manufacturer, or an additional gemstone can drive up the price. With coins, such an increase in price can be caused by the age, the country of origin or the depicted motif. A certain amount of expertise is required to determine value, and possible increases in the value of new coins are usually associated with speculative risks.

Small objects are usually easier to sell:

Even though the premium for smaller objects is higher, they are often easier to sell. You can both turn part of the investment amount back into cash (cutting up large bars reduces the sale value) and, in social crises, better use the small pieces as barter items.

Buy from the dealer or check for authenticity yourself with private sellers:

It is advisable to buy gold and other precious metals from reputable dealers. Otherwise, if one would like to save e.g. the value added tax (amounts to with precious metals except gold after all 19%) by private purchase, it should be examined whether the precious metal is genuine. The necessary tests can either be done by yourself (e.g. with the GoldScreenSensor) or by a precious metal dealer.

Purchase gold locally instead of buying a fake on the Internet:

It is not advisable to buy precious metals via private online trading platforms such as Ebay or Amazon, as fraudsters have an easy game there. It often happens that customers assume they have made a good deal and then only receive a fake made of copper with a thin layer of gold. However, if there is ever a genuine offer on these platforms, it is usually overpriced, as platforms such as Ebay or Amazon always demand fees from sellers. A personal sales meeting is preferable to sending a package when buying privately to be able to verify authenticity. Scammers would not allow you to do your own verification nor give you a return policy.

Hallmarking is not essential, yet it is not unimportant:

Hallmarking is standard on newer coins, jewellery or bars. In addition to the fineness, it sometimes provides further information about the precious metal, e.g. which manufacturer it comes from, what material it is made of or when the piece was manufactured.

What to do if the answer is unexpectedly right or wrong? (DensityScreenScale)

We suggest that you repeat the measurement. Before a second measurement, please follow the steps below:

  1. Check that all components of the density measurement assembly are firmly seated on the scale and correctly arranged.
  2. If a completely unexpected result appears, restart the device and wait a few minutes.
  3. Carefully dry all components that should not be in contact with the water bath.

Now the scale should give you a valid result.

In addition, it may be that there are cavities in the material that are not visible from the outside or that the object is more porous on the inside than it appears from the outside. Also not expected contamination with denser or less dense materials/substances can be responsible for a wrong answer.

If you have any further questions, please do not hesitate to contact us.

Can the magnetic scale be replaced by a single magnet?

Yes and no. Theoretically, it is possible to detect with a magnet whether an object has a dia- or paramagnetism. However, the magnetic forces of conventional magnets are often so low that they cannot be detected with the human eye. Therefore, a very strong magnet is needed for a measurement. We recommend the MagneticScreenScale that can measure down to hundredths of a gram. This enables the detection of very fine differences and the achievement of clear results.

How long does the battery of my GoldScreenSensor/GoldScreenPen last and can I replace it myself?

The battery lasts for over 10 hours of active use. The charging process takes about 2 hours.

If you would like to have the battery of your device changed, please contact us and we will do it for you.

Methodological terms for measuring precious metals


  • Density of a body describes its mass in relation to its volume
  • "Pseudo-density" can be calculated from the dimensions and weight of the object at hand
  • Each material has a specific density


  • Conductivity is the ability of a substance to transfer energy (e.g. electricity, heat)
  • It is measured in megasiemens per metre
  • Our devices measure conductivity using inductive eddy current measurement


  • Diamagnetism = the occurrence of a magnetic field (magnetisation), when an external magnetic field is applied to a substance, whereby the magnetisation opposes the external field. Summary: diamagnetic materials are repelled by the magnet.
  • Paramagnetism = form of magnetism in which a substance shows no measurable magnetic moment in the absence of an external magnetic field, but acquires a magnetisation in the presence of an external field. Summary: Paramagnetic materials are slightly attracted to the magnet.
  • Ferromagnetism = By applying an external magnetic field, the elementary magnets align themselves in the same direction. The ferromagnetic material itself becomes a magnet. Summary: Ferromagnetic substances are attracted to the magnet.

Susceptibility properties:

  • Describe the ratio of the magnetisation of a material to the magnetic field strength
  • This so-called magnetic susceptibility can be measured with the help of a magnetic balance
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