9 or 18 carat gold: which difference to choose for your jewelry?

Gold is a precious metal highly prized in jewelry, but not all gold jewelry is equal. Two of the most common alloys are 9 carat gold and 18 carat gold. So, what are the differences between these two types of gold?

9 carat gold, 375/1000 gold, 18 carat gold, 750/1000 gold: what's the difference?

When talking about gold in jewelry, the terms "375/1000" and "750/1000" often come up. This is a notation indicating the proportion of pure gold in the alloy used.

• 9 carat gold (375/1000) : Contains 37.5% pure gold, or 375 thousandths of gold out of a total of 1000.
• 18 carat gold (750/1000) : Contains 75% pure gold, or 750 thousandths of gold out of a total of 1000.

These values allow you to know the exact amount of gold in a piece of jewelry. The higher the percentage, the more precious and durable the jewelry is.

What is 9 carat gold and 18 carat gold?

Composition and purity of gold

Pure gold, known as 24 carat, is too malleable to be used as is in jewelry. It is therefore alloyed with other metals (silver, copper, palladium, etc.) to make it more resistant.

• 18 carat gold : Contains 75% pure gold (or 750 thousandths), the rest being alloy metals.
• 9 carat gold : Contains 37.5% pure gold (or 375 thousandths), supplemented by a higher proportion of alloy metals.

Thus, 18 carat gold is considered more noble and more precious than 9 carat gold.

Price differences between 9 and 18 carat gold

The price of a gold piece of jewelry depends on its pure gold content. Naturally, an 18 carat gold piece of jewelry will be more expensive than a 9 carat gold piece, as it contains a higher proportion of gold.

• 18 carat gold : More expensive because it is richer in pure gold.
• 9 carat gold : Cheaper, which allows for obtaining gold jewelry at a lower cost.

The choice between these two types of gold will therefore depend on your budget and your preferences in terms of quality.

Durability and resistance of 9 and 18 carat gold

Contrary to popular belief, 9 carat gold is harder than 18 carat gold. However, this greater hardness does not mean that it is more resistant to shocks or scratches.

• 18 carat gold : More malleable but more resistant to oxidation and corrosion.
• 9 carat gold : Harder, but more prone to oxidation due to its higher proportion of alloy metals.

Appearance and colors of 9 and 18 carat gold

The alloy with other metals influences the color of the gold. The higher the gold content, the warmer and more intense the color will be.

• 18 carat gold : More intense and richer color.
• 9 carat gold : Lighter shade, sometimes less warm.

Regarding white gold, 9 carat gold may yellow faster than 18 carat gold because it contains more metals that oxidize.

Maintenance of 9 and 18 carat gold jewelry

Regardless of the type of gold, good maintenance is essential to preserve the beauty of your jewelry.

• 18 carat gold : Easier to maintain as it oxidizes less.
• 9 carat gold : Requires more regular cleaning to prevent oxidation and maintain its shine.

It is recommended to avoid exposure to moisture, chemicals and to store jewelry in a case when not worn.

To differentiate 9 carat gold from 18 carat gold, one can refer to the hallmarks.

• 18 carat gold hallmark: A hallmark in the shape of an eagle's head or the marking 750.

• 9 carat gold hallmark: A hallmark in the shape of a clover or the marking 375.

These official marks guarantee the gold content and authenticity of the jewel.