Is my Omega solid gold or gold-plated?
This is the question worth the most money, and the one people get wrong most often. A solid 18k Omega case from the 1960s holds around three thousand dollars of gold at today's prices. The same watch gold-capped or plated holds essentially none. They photograph identically.
Think yours might be solid gold?
Weigh it and the melt value comes back free. For the full answer on the watch, send six photos.
Three ways to settle it. The first two take a minute. The third is conclusive and costs nothing.
Method one
The hallmark
Solid gold cases are stamped with their fineness. Look inside the caseback, and on the case band under the lugs. You're looking for a small number.
| Stamp | Means |
|---|---|
| 750 | 18 karat, 75% gold |
| 585 | 14 karat, 58.5% gold |
| 375 | 9 karat, 37.5% gold |
Older or British-market cases may show 18K, 14K or 9ct instead, or an assay office mark. Swiss cases often carry a small helvetia head or a squirrel alongside the number.
No fineness stamp anywhere means it is not solid gold. There is no exception to that worth betting money on. Gold cases were legally required to be marked, and the marks survive polishing better than people expect — check under the lugs, where the buffing wheel never reached.
Method two
The case code
Omega stamps a two-letter code inside the caseback telling you what the case is made of. Solid gold cases carry the code and a fineness number together. Plated and capped cases carry a code with no fineness mark at all.
If you can read a code but can't find a 750, 585 or 375 anywhere near it, that's your answer.
Method three
The water test
This is the one that settles arguments. It measures density, and density cannot be faked by plating. You need a kitchen scale reading to 0.1g, a glass of water, and a bit of thread.
- Take the movement and dial out, or have someone do it. You're weighing the bare case, nothing else. If you can't open it, send it to me.
- Weigh the bare case dry. Write it down. Call it A.
- Hang the case from the thread so it's fully underwater and touching nothing — not the bottom, not the sides.
- Weigh it again while it's suspended. Call it B.
- Divide: A ÷ (A − B). That's the density.
| Density | What it is |
|---|---|
| 15.1 – 15.6 | solid 18k |
| 13.0 – 13.4 | solid 14k |
| 11.3 – 11.7 | solid 9k |
| 8.0 – 8.9 | brass core — capped, filled or plated |
| 7.7 – 8.0 | stainless steel |
There is no middle ground between 8.9 and 11.3. A case is either solid or it isn't, and this tells you which in about five minutes.
The arithmetic
What the gold is actually worth
Once you know it's solid, it's straightforward. Weigh the bare case, multiply by the fineness, multiply by the gold price per gram.
A worked example. A 34mm 18k Constellation case, movement out, weighs about 27g.
27 g × 0.75 = 20.25 g fine gold
Roughly three thousand dollars of metal sitting in your hand.
A refiner will pay you around 85% of that. Which is exactly why people get offered scrap value. It's a fast, easy number for the buyer, and it's almost never the best one for you.
The part that matters
Every old Omega is worth three different numbers
Knowing the metal is only half of it. Your watch is worth the highest of these, and they are rarely the same.
Most people are only ever quoted the third number. That's the whole reason this page exists. The three values, in full.
If you're stuck
Send me photos
Can't open it, can't find a mark, can't read the code — that's normal, and it's what I do. Send photographs of the movement, the inside of the caseback, the dial, and the case from both sides, plus the total weight on a kitchen scale. I'll tell you what it is, what's in it, and which of the three numbers applies.
No charge for this. Phone photos are fine. Email id@watchbreaker.com, subject "Gold or plated?". If you'd rather know the calibre and its age too, use the subject "What is it?" instead — same price, which is nothing. How it works.
I'm not affiliated with Omega or the Swatch Group. Everything above is measurement and public record. Watch Breaker is an independent identification specialist and parts dealer. Omega is a trademark of Omega SA. Terms.