When buying a gold jewel, the mention 18 karats, 14 karats or 9 karats often appears in its description. These indications refer neither to the weight of the jewel nor to that of the stones: they correspond to the proportion of pure gold present in the alloy.
As pure gold is naturally soft, it is mixed with other metals so that it can be transformed into rings, bracelets, necklaces or earrings strong enough for daily wear.
Understanding the difference between 18, 14 and 9 karat gold therefore makes it possible to better appreciate the quality, durability and real value of a jewel.
What does the number of karats mean for gold?
The purity of gold is expressed on a scale of 24 karats.
A 24 karat gold jewel is composed almost entirely of pure gold. However, this metal is relatively malleable and less suitable for certain settings intended for daily wear.
The main purities used in jewelry are:
- 18 karat gold: 750 thousandths of pure gold;
- 14 karat gold: 585 thousandths of pure gold;
- 9 karat gold: 375 thousandths of pure gold.
The rest of the alloy consists of other metals, such as silver, copper, palladium or sometimes zinc, depending on the desired color and properties.
What is 18 karat gold?
18 karat gold contains 75% pure gold and 25% other metals.
It is particularly prized in high-end jewelry due to its high gold content, its brilliance and its good resistance when properly alloyed.
It is frequently used for antique jewelry, jewelry pieces and settings with precious stones.
Its main advantages are:
- a high proportion of pure gold;
- a generally richer color;
- good resistance in normal use;
- a higher intrinsic value;
- excellent longevity when well maintained.
18 karat gold often represents a good balance between purity, beauty and solidity.
What is 14 karat gold?
14 karat gold contains 58.5% pure gold and 41.5% other metals.
It is very common in certain countries, particularly for jewelry intended for daily wear. Its higher proportion of alloying metals can give it good hardness, depending on its composition.
Its yellow color is generally a little less intense than that of 18 karat gold.
14 karat gold has several characteristics:
- good resistance to use;
- a generally more accessible price than 18 karat gold;
- a higher gold content than 9 karat gold;
- a color that varies according to the metals used in the alloy.
It represents an intermediate solution between 18 karat gold and 9 karat gold.
What is 9 karat gold?
9 karat gold contains 37.5% pure gold and 62.5% other metals.
Even if it is legally sold as gold in several countries, pure gold does not constitute the majority of its alloy.
It is generally more affordable than 14 or 18 karat gold. Its color can also be less intense and its behavior depends heavily on the nature of the other metals used.
9 karat gold can have:
- a more accessible purchase price;
- a lower pure gold content;
- a lower material value;
- a sometimes lighter color;
- a higher risk of oxidation or surface modification depending on the alloy and conditions of use.
However, the quality of a jewel should not be judged solely by its carat number. Manufacturing, condition, weight, signature and stones also influence its value.
What is the color difference between 18, 14 and 9 karat gold?
The higher the proportion of pure gold, the richer and deeper the yellow color can naturally be. However, the final color also depends on the other metals added to the alloy.
Two 18 karat gold jewels can therefore have slightly different nuances.
The addition of copper generally gives a warmer or pinker tone, while some lighter metals are used to produce white gold.
There are thus three main gold colors:
- yellow gold;
- rose gold;
- white gold.
Color alone therefore does not make it possible to determine the number of karats. The hallmarks must be examined or the metal tested.
Is 9 karat gold necessarily more resistant?
One might think that a jewel containing less pure gold is always stronger. In reality, this depends on the exact composition of the alloy and the manufacture of the jewel.
A metal-richer alloy can be harder, but that does not necessarily mean it will withstand all types of wear better. Some alloys can be more brittle, more susceptible to oxidation, or less easy to repair.
Resistance also depends on many elements:
- the thickness of the jewel;
- the quality of the setting;
- the type of setting;
- the solders;
- previous transformations;
- how the jewel is worn.
A thin 18 karat gold ring can be more fragile than a massive 14 karat gold ring. The number of karats should therefore never be analyzed in isolation.
What are the gold hallmarks?
Hallmarks provide indications on the nature and purity of the metal. They can be stamped inside a ring, on the clasp of a bracelet, near the carabiner of a chain or on the back of a pendant.
Numbers indicating the purity may be found, in particular:
- 750 for 18 karat gold;
- 585 for 14 karat gold;
- 375 for 9 karat gold.
Antique jewelry may also bear guarantee hallmarks, master's hallmarks or import marks.
The absence of a perfectly legible hallmark does not automatically mean that the jewel is not gold. Over time, a hallmark may be worn, partially erased or have disappeared as a result of resizing or repair.
An expert appraisal or a professional test can then confirm the nature of the metal.
The study of hallmarks, metal and manufacturing techniques also makes it possible to recognize an authentic vintage jewel.
Which gold to choose for an antique jewel?
To choose between 18, 14 or 9 karat gold, several criteria must be taken into account:
- the budget;
- the frequency of wear;
- the desired color;
- the weight of the jewel;
- the quality of manufacture;
- the presence of stones;
- the general condition of the piece;
- its historical or jewelry value.
For an antique jewel or a piece of jewelry intended to retain significant value, 18 karat gold is generally particularly sought after.
However, a 14 or 9 karat gold jewel can also be of genuine interest when it has a beautiful design, quality craftsmanship, a signature or a particular history.
Does the number of karats entirely determine the value?
No. The gold content is an important criterion, but it is not enough to determine the price of a jewel.
Two 18 karat gold rings of similar weight can have very different values depending on:
- the quality and weight of the stones;
- the era;
- the signature;
- rarity;
- the craftsmanship;
- the state of preservation;
- market demand.
The value of an antique jewel therefore does not correspond solely to its gold weight. A complete expert appraisal must take into account all of its characteristics.
To delve deeper into this topic, discover why two similar jewels can have very different values.
How to care for a gold jewel?
Gold does not rust, but its surface can tarnish or become covered with soap, cream and dust residues.
A gold jewel can generally be cleaned with warm water, a small amount of mild soap and a non-abrasive cloth, provided that its stones and setting allow it.
You should avoid:
- toothpaste;
- abrasive products;
- bleach;
- chlorine;
- hard brushes;
- too frequent or too aggressive cleaning.
For an antique, set or fragile jewel, checking with a jeweler is preferable before any thorough cleaning.
Find all our advice on how to clean and care for antique jewelry without damaging it.
GemmeLuxe Expertise
At GemmeLuxe, each piece of jewelry is carefully examined to identify the nature of the metal, hallmarks, stones and main manufacturing characteristics.
Our descriptions specify, when identifiable, the gold purity and useful elements to understand the quality and value of each piece.
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