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The fineness of gold and the composition of gold

Published: 2020-10-27
Edited: 2026-11-10
Airidas Ulevičius
Airidas Ulevičius
Founder and Director of Auksinė svajonė, Master Jeweller

Gold fineness indicates the proportion of pure gold in a jewelry alloy. For example, a fineness of 585 means that out of 1,000 parts by weight of the alloy, 585 parts or 58.5% are pure gold. In Lithuania, the standard gold finenesses are 375, 585, 750, 916, and 999.

In a nutshell: What does gold fineness mean?

The higher the fineness number, the greater the proportion of pure gold in the alloy. Therefore:

  • 375 fineness – 37.5% pure gold;
  • 585 fineness – 58.5% pure gold;
  • 750 fineness – 75% pure gold;
  • 916 fineness – 91.6% pure gold;
  • 999 fineness – 99.9% pure gold.

However, a higher fineness does not necessarily mean that the jewelry will be better suited for everyday wear. Other important factors to consider when choosing jewelry include the alloy’s properties, the jewelry’s design, thickness, intended use, and how often it will be worn.

What is gold fineness?

Pure gold is a soft and highly malleable metal. For this reason, most gold jewelry worn daily is made not from nearly pure gold, but from gold alloys. Other metals are added to the alloy along with gold. These metals allow the mechanical properties and color of the alloy to be modified, making it suitable for various types of jewelry.

The fineness indicates the amount of pure precious metal per thousand parts by weight of the alloy. For example:

585 / 1000 = 58.5% pure gold. The remaining 41.5% of the alloy consists of other metals.

Gold Fineness Chart

Gold purity Amount of pure gold Approximate equivalent in carats Where is it more common?
375 37,5 % 9K In jewelry
585 58,5 % 14K Very commonly in everyday jewelry
750 75 % 18K In high-karat jewelry
916 91,6 % 22K In high-purity gold items
999 99,9 % ~24K Almost pure gold

Important: The fineness indicates the amount of gold in the alloy, not the overall quality of the jewelry. Two rings of the same fineness can vary greatly in their construction, weight, craftsmanship, gemstones, and final value.

375 fineness - how much gold is in it?

375 fineness means that the alloy contains 37.5% pure gold. In the karat system, this corresponds to 9K gold. The remaining 62.5% of the alloy consists of other metals. Since the proportion of pure gold is lower than in 585- or 750-fines alloys, a 375-fine piece will contain less pure gold than a piece of the same mass made from a higher-fine alloy.

However, fineness alone is not a reliable indicator of a piece of jewelry’s overall quality. The quality of craftsmanship, design, weight, and materials used are also important.

585 fineness - what does it mean?

585 fineness means that 58.5% of the alloy’s mass consists of pure gold, while the remainder consists of other metals used in the alloy. In the karat system, 585 fineness corresponds approximately to 14-karat gold.

585-fine gold is extremely common in jewelry because it combines a significant amount of pure gold with the practical properties of the alloy.

It is used to make:

  • wedding and engagement rings;
  • earrings;
  • chains and pendants;
  • bracelets;
  • other gold jewelry worn daily.

The Auksinės Svajonės wedding ring collection features many 585-fineness models.

How much pure gold is in a 585-fineness ring?

If the mass of the ring’s gold alloy is 5 g, the theoretical amount of pure gold is calculated as follows:

5 × 0.585 = 2.925 g of pure gold.

This is a calculation of the alloy’s composition, not a formula for determining the value of the jewelry. If the piece contains gemstones or other materials, the total weight of the jewelry cannot automatically be considered the weight of the gold alloy.

750 fineness - how does it differ from 585?

750 fineness gold contains 75% pure gold. It corresponds to the 18-karat system. A 750 fineness alloy contains more gold, so it is chosen when a higher proportion of pure gold is important.

However, for an everyday ring, the highest fineness is not the only criterion. Durability is influenced by the specific composition of the alloy, the ring’s profile, thickness, construction, and wearing habits.

What do the gold finenesses 916 and 999 mean?

916 fineness

A 916 fineness means that the alloy contains 91.6% pure gold. This corresponds approximately to the 22K system. The purity of this gold is significantly higher than that of 585 or 750 fineness, but due to the higher proportion of gold, its properties differ from those of typical everyday jewelry alloys.

999 fineness

999 fineness contains 99.9% gold. It is often referred to as nearly pure gold and roughly corresponds to 24K. Due to the softness of gold, this fineness is not a typical choice for many rings worn intensively on a daily basis.

How to choose the fineness of gold for a piece of jewelry?

When making your choice, it’s worth answering three questions.

1. How often will you wear the piece of jewelry?

For a ring worn daily, it’s not just the percentage of pure gold that matters, but also practicality, construction, and durability for everyday use.

2. How important is a higher gold purity?

If you want a higher percentage of pure gold, you can choose 750 fineness. If you’re looking for a fineness commonly used in jewelry for everyday wear, consider 585 fineness.

3. What color of gold do you want?

Fineness and color are two separate choices. Gold of the same fineness can come in different colors, so you can first choose the desired fineness and then select the alloy’s shade.

If you can’t find the combination you want, when having jewelry custom-made, you can work with a jeweler to determine the appropriate metal, fineness, color, and design.

Frequently Asked Questions

What is the best gold fineness?

There is no single “best” gold fineness - the most suitable one depends on the jewelry’s intended use:

  • For everyday jewelry, 585 fineness is often a practical choice, as it contains 58.5% pure gold, and the remaining alloy components allow the jeweler to achieve the desired mechanical and color properties.
  • A 750 fineness is suitable for jewelry requiring a higher percentage of pure gold and a higher fineness.
  • A 375 fineness has a lower percentage of pure gold - 37.5%.
  • 916 and 999 fineness grades are characterized by a very high concentration of gold. As the amount of pure gold increases, the alloy generally becomes softer; therefore, very high fineness grades are not automatically the best choice for every piece of jewelry intended for everyday wear.

If you’re choosing an engagement ring or wedding bands, it’s worth considering not only the fineness but also the ring’s design and how it will be worn.

What’s the difference between fineness and karats?

Gold purity can be measured using two systems:

  • The fineness system indicates the number of parts of gold out of 1,000. For example, 750 means 750 parts of gold out of 1,000, or 75%.
  • The karat system divides total gold purity into 24 parts. Therefore, 24K means nearly pure gold, while 18K means approximately 75% gold.

It is important not to confuse gold karats (K) with the carat (ct), a unit of weight used for gemstones. The names are similar, but they are completely different measurements.

Does the color of gold indicate its fineness?

No. It is not possible to reliably determine the fineness of gold based solely on the color of the jewelry. White, yellow, and rose gold can all have the same fineness, such as 585 or 750. The color depends on the remaining composition of the alloy and the final finishing of the jewelry.

Therefore, when evaluating an unknown piece of jewelry, one should not judge its purity based solely on color.

Does a higher fineness mean a more expensive piece of jewelry?

If we were to compare gold alloys of the same weight, the alloy with the higher fineness would contain more pure gold. However, the final price of a piece of jewelry depends on more than just the fineness. It can be influenced by:

  • the weight of the jewelry;
  • the complexity of production;
  • the design;
  • precious stones;
  • their quality and weight;
  • handcrafting;
  • the condition and origin of the jewelry.

Therefore, for example, a lightweight 750-karat ring will not necessarily cost more than a heavier 585-karat ring set with gemstones. If you’re interested in having a piece of jewelry you already own appraised, you can find more information on the gold buying page.

Are you choosing a gold piece of jewelry?

Gold fineness helps you understand how much pure gold is in the alloy, but the right piece of jewelry is chosen by evaluating its construction, color, design, and the gemstones used.

Browse Auksinė Svajonė's wedding rings or contact us about custom jewelry if you’d like to choose the gold fineness, color, and design that are specifically suited to your piece.

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