Gold Purity Measurements – 5 Things That You Should Know

Gold Purity Measurements - 5 Things That You Should Know

From the very beginning of times, gold has always been an attraction for civilizations.

It is a symbol of power, purity, rarity and beauty. Not only this precious metal is a beauty that people use as embellishments, but it is also a powerful metal that comes with several important chemical properties.

Gold is an excellent conductor of electricity. It is highly stable and completely non-reactive so it does not oxidize or lose its physical attraction. In its purest form, gold is malleable so it can attain almost any shape without breaking.

And lastly, it is difficult to extract so its difficult accessibility further contributes towards its value.

All the characteristics highlighted above makes gold one of the few commodities that can also be thought of as a currency or monetary asset.

Since ages and even today, gold is considered to be a rare precious commodity and governments and investors around the world invest in it to guard against inflation and sustain the value of their money.

Moreover, its physical and chemical properties and rarity also make it one of the most precious metals for investment.

If you are planning to invest in gold, there are several things that you need to consider, with purity being the most important consideration. In this post, you will learn 5 things about gold purity measurement so you can make a more confident investment.

Karat and Fineness are Two Standards of Gold Purity Measurement


The standardized gold purity measure is known as the Karat. Outside the U.S., it is often spelled as carat. However, carat is used as a measure to weigh gems so make sure you don’t confuse it with the measure of gold purity.

A karat measures the purity of gold expressed as the number of parts of gold it contains out of 24 and is stamped on the gold piece as K or KT. So a gold bar labelled as 16K or 16KT means that the alloy contains 16 parts of gold, whereas 8 parts of other metals.

This gold purity measurement uses a scale of 0 to 24 so the higher the karat number, the more gold content it contains. However, 24 karat is the purest gold you can buy.

One thing to remember here is that gold in its purest form is super soft given its malleability; therefore, some impurity (in the form of other metals) is always present to make sure that the metal retains its shape. Metals that are often used with gold include copper, zinc, silicon, silver and palladium.

So the 24- karat piece of gold, whether in the shape of a coin or bar, will not be 100% pure. Minimal impurity in the form of other metals will be present, so you get 99% or 99.9% pure gold when you purchase 24-karat gold in any form.

In all, a karat refers to the ratio of gold and other metals in your gold. Another gold purity measurement that is commonly used in known as Fineness. Let’s look at what it means and how to interpret it.


Fineness, also known as millesimal fineness, is another system of gold purity measurement.

Just like karat, it refers to the percentage of gold in a certain alloy using parts per thousand. So a gold alloy that is 999 fine means that it is 99.9% pure, whereas a fineness of 750 means that it contains 75% gold and 25% other metals.

Both karats and fineness are used as gold purity measurement. Now let’s learn how to use these two measures to find out how pure your gold is.

Karats and Fineness Can be Used to Calculate Gold Purity

Using the number of karat and fineness, you can measure how pure your gold is. Let’s find out how to do it.

KaratsRatio of Gold to Other MetalsFinenessPurity
24K1:0 (minimal impurity added)99999.9&

If you know the karat or fineness, you can easily figure out how pure your gold is. In the table above, look at the 9K alloy. It means that your piece of metal contains 9/24 parts of gold, whereas the other 13 parts are of other metals, including copper, palladium or silver. =

Similarly, you can use the karat reading to find out the fineness. Since fineness is the measure of purity in terms of the percentage of gold in an alloy, you will can find out fineness using the formula (Karat/24)*1000. The resultant that you get is the fineness or percentage purity.

Here it is important to note that even the 24-karat gold bar is not 100% pure because a minimal impurity (other metals) is added so that the gold bar can retain its shape.

Now that you are aware of the two gold purity measurements, you can now understand how gold purity affects its most obvious characteristic – its color.

Gold Purity Affects Gold Colors

Gold Purity Affects Gold Colors

In its purest form, the 24-karat gold has a warm, gold color that you cannot change unless you add an impurity in the form of another metal.

Because of this reason, the 24-karat gold bar that you can find on the market has a distinct color, which is quite different from the jewelry that you see at jewelry shops.

When different metals are added to pure gold, it changes the composition of the alloy, which is reflected in the form of modified color. Some of the different colors of gold alloy that you can find include:

Rose Gold 

The slightly pink-hued gold that is available on the market is an alloy of gold and copper.

The inclusion of copper to the brightly colored gold gives a unique pink shade. The alloy with copper is often referred to as rose gold.

Green Gold

Very often, gold is combined with metals, such as zinc and silver.

When more of these metals are added to pure gold, you get a slight green tinge. Usually, 14K gold is greenish in color.

White Gold

As the name suggests, white gold is white in color and the result is achieved by adding palladium or nickel. It is common to assume that white gold is the same as platinum, whereas the reality is different.

Platinum in its purest form possesses more than 95% of the metal platinum, whereas white gold is an alloy containing gold, nickel, zinc, palladium and silver.

Apart from that, electro plating can also be used to give it a unique surface color. However, this does not affect the purity of gold.

Hallmarks Serve a Purpose

Hallmarks Serve a Purpose

As you intend to invest in physical gold, it is important to verify the hallmark because hallmarks indicate gold purity. If you are unaware of what a hallmark is, it refers to an official mark or stamp that certifies gold’s purity.

Therefore, every piece of gold that you purchase, whether in the form of jewelry or as a gold coin or bar, make sure you check the hallmark. Typically, a hallmark is stamped behind the jewelry but stamping laws may vary by country.

Moreover, it is possible that you may come across an unstamped piece of gold. In that case, you can check for purity by using one or more of the gold purity verification methods that are highlighted in the next section.

You Can Verify Gold Purity Using Several Measures

You Can Verify Gold Purity Using Several Measures

Gold purity has always been the primary concern when investing in this precious commodity and while hallmarks serve a purpose, it is possible that you may end up investing in faux metal.

To reduce the risk of investing in a counterfeit metal, you can try several methods for determining gold purity. Some of the measures include the following.

Fire Array

It is the most accurate method of determining gold purity.

It involves removing a piece of metal and exposing it to acid test to find out gold purity.

X-ray Fluorescence

X-ray fluorescence is another method of gold purity measurement.

However, it is not as accurate as fire array.

Touchstone Testing Process

A simpler and relatively non-technical way to assess gold purity is touchstone testing. Just like fire array, this method also requires the use of an acid for gold purity measurement.

Regardless of which method you use to assess gold purity, it is best to begin by checking the hallmark or stamp. Often, hallmarks give the most accurate analysis but in case there is no stamping or hallmarks, you can try one or more of the above methods for assessing gold purity.

Gold will continue to be a precious commodity for years to come and its purity will remain the primary consideration. With the information highlighted in this post, we are confident that you have a better understanding of several aspects of gold purity measurement.

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