As a goldsmith, I’m often asked about the difference between 9 karat, 14 karat and 18 karat gold. The answer is both technical and aesthetic — and it plays an important role in how I design and make my jewellery.
What Does Karat Mean in Gold?
Unlike carat, which measures the weight of gemstones, karat refers to the proportion of pure gold in a metal alloy.
The term originates from Greco-Roman systems of measurement. The Romans used a coin called the solidus, which was divided into 24 parts. Over time, this evolved into the karat system we use today.
Gold purity is measured on a scale from 0 to 24:
- 24 karat = pure gold
- Lower numbers = gold mixed with other metals
The higher the karat, the higher the gold content.
Why Pure Gold Isn’t Used in Jewellery
Pure 24 karat gold is beautiful, but it is also very soft and malleable. This makes it unsuitable for most jewellery, which needs to withstand everyday wear.
By adding other metals — typically silver and copper, and sometimes palladium — gold becomes stronger and more durable. These alloys also influence the colour and character of the finished piece.
Nickel was historically used but is now largely avoided due to its potential to cause allergic reactions.
9k vs 14k vs 18k Gold
The karat number tells you how much pure gold is in the alloy:
| Karat | Gold Content | Alloy Content | Appearance |
|---|---|---|---|
| 24K | 24/24 | 0/24 | Rich, orangy-yellow |
| 18k | 18/24 | 6/24 | Warm, buttery yellow |
| 14k | 14/24 | 10/24 | Soft, straw yellow |
| 9k | 9/24 | 15/24 | Subtle, pale yellow |
What This Means in Practice
- 18k gold has a richer colour and higher value.
- 14k gold offers a balance between colour and durability.
- 9k gold is more subtle in tone and less hard-wearing.
The higher the gold content, the higher the price — but also the softer the metal.
Gold Purity and Hallmarking
Another way to express gold content is through millesimal fineness, which measures purity in parts per 1000.
| Karat | Gold | Fineness |
|---|---|---|
| 24K | 99.9% | 999 |
| 18k | 75.0% | 750 |
| 14k | 58.3% | 583 |
| 9k | 37.5% | 375 |
This is the system used by assay offices when hallmarking jewellery.
Gold Standards Around the World
Different countries favour different gold purities, often for cultural or historical reasons:
- 22k — common in the Middle East and Asia
- 18k / 14k — widely used in continental Europe
- 9k — common in the UK and Ireland
- 10k — often used in the United States
- 15k — found in antique jewellery
Why I Work With 9k, 14k and 18k Gold
In my own work, I use different gold alloys depending on the piece and its purpose.
In the Summer Strand collection, 14k gold allows for strength and ease of wear, making it well-suited to everyday jewellery.
For one-of-a-kind pieces, I often choose 18k gold, where the warmth and richness of colour become an integral part of the design.
Each alloy has its own character — and choosing between them is part of shaping how a piece looks, feels and behaves over time.
Gold, Wearability and Everyday Life
Jewellery is made to be worn.
The choice of gold affects not only how a piece looks, but how it performs in daily life — its durability, weight, and the way it ages over time.
Whether subtle or richly coloured, each alloy offers a different balance between strength, beauty and longevity.
Explore Further
If you’d like to see how these materials come together in finished pieces: