Comparison
18ct gold or 9ct gold?
9ct gold is meaningfully harder, so if your hands take a beating the choice is largely made for you.
| 18ct gold | 9ct gold | |
|---|---|---|
| Surface hardness | Mohs 3 | Mohs 3.5 |
| Density | 15.6 g/cm³ | 11.2 g/cm³ |
| Resizable | Yes | Yes |
| Hallmarked | Yes | Yes |
| Hypoallergenic | Alloy dependent | Alloy dependent |
| Price from | £795 | £395 |
What the difference actually feels like
18ct gold is 1.4 times the weight of 9ct gold for the same ring. On paper that is a number; on the hand it is the difference between a ring you forget about and one you are aware of every time you move. Neither is better. It is worth knowing which you want before you spend anything.
9ct gold sits at Mohs 3.5 against 3. Ordinary household dust carries quartz at Mohs 7, which is the line that matters: below it a ring collects fine scratches from nothing more than daily life. The gap here is real but not dramatic.
The straight answer
Choose 18ct gold if depth of colour, or if weight on the finger.
Choose 9ct gold if a traditional ring on a real budget, or if anyone who wants it resizable for life.
Still torn? The metal chooser asks six questions and picks one, and it will tell you if neither of these is right.
In both materials
Rings to look at
Common questions
- Is 18ct gold or 9ct gold harder wearing?
- 9ct gold, at Mohs 3.5 against 3. Airborne dust contains quartz at Mohs 7, so anything below that scratches from ordinary wear alone.
- Which is heavier?
- 18ct gold, at 15.6 g/cm³ against 11.2. That is 1.4 times the weight, which is very obvious on the hand rather than a technicality.
- Can both be resized?
- Yes, both. Either can be sized up or down by a bench jeweller, and we do it free.
- Which costs more?
- 18ct gold, starting at £795 against £395. That is about 101% more before any stone or inlay.
- Are both hallmarked?
- Yes, both, at the Birmingham Assay Office.