Rolex, since its inception, has always dedicated itself to excellence.
During a short period in the 1960s to 1970s, Rolex and other luxury watch brands began to mark some watches with the Greek letter sigma (σ). It served as a promise of quality, indicating the presence of precious metals in the model.
In this blog, we will discuss how to recognize a sigma dial, the meaning behind the marking, and market value of the watch.
How to Identify a Rolex Sigma Dial
You can spot a Rolex sigma dial by the tiny Greek sigma letters printed at the bottom of the dial.
Most Rolex dials from the 1960s–70s read “T SWISS T” at 6 o’clock (denoting tritium lume). A sigma dial, however, is marked “σ T SWISS T σ.”
In other words, a small “σ” sandwiches each side of the SWISS designation. These confirm that the hour markers (and often hands) are solid gold.
If a vintage Rolex has this marking, it’s a true sigma dial.
Enthusiasts should also ensure the watch’s production year aligns with the 1970s, since a sigma mark on a non-1970s Rolex would indicate a later service dial or an incorrect replacement.
What the Sigma Symbol Means on a Rolex
In the 1970s, as a response to rising competition from cheap quartz watches, a group of Swiss watchmakers formed an initiative to highlight the use of gold in watches. The APRIOR (the Association for the Industrial Promotion of Gold), wanted to highlight the value of the gold in participating Swiss-made watches.
The solution they found was to begin marking dials with the Greek letter sigma (σ), as a subtle indicator of precious materials in the watch.
The “σ” mark under the 6 o’clock mark on a Rolex dial specifically signifies that the watch’s hour markers and hands are made of, typically, 18k gold.
This was especially useful on stainless steel models, where white gold markers might otherwise look like steel. By printing “σ” symbols on the dial, Rolex could assure buyers that those shiny indices were actually solid gold, not merely steel or plated metal.
Rolex Sigma Dial Market Value
The sigma dial was primarily a feature of Rolex’s dress and chronograph lines, where applied metal indices were used. It often appears on steel-cased Rolexes (to highlight white gold details on the dial) but can also be found on two-tone and gold models of the era.
Many classic Rolex models during this short period of time can be found with sigma dials.
Notably, the Datejust 1601 and 1603, the Day-Date 1803, the Date/Oyster Perpetual Date, and the Cosmograph Daytona (manual-wind models like ref. 6263 and 6265) were produced with sigma dials. Even dressy Cellini watches received sigma markings.
Among vintage Rolex collectors, sigma dials are a prized detail. Because Rolex only used the sigma symbol for a handful of years, these dials are relatively scarce, and that small σ can add a lot of value to an otherwise common reference.
Collectors appreciate such nuances as part of a watch’s history.
A sigma dial is a talking point, a little secret sign of the 1970s!
In today’s market, for example, a vintage Daytona or Datejust with an original sigma dial will often command a premium over equivalent models without it.
Rare and completely original Daytona sigma models can sell for around $100,000! Datejust sigma models can sell for anywhere between $4,000 to $9,000 and up.
Sigma dials encapsulate a time when Swiss brands banded together to celebrate traditional craftsmanship and intrinsic value during the quartz onslaught.
For Rolex enthusiasts, hunting down a crisp sigma dial variant of a beloved reference is a rewarding endeavor. It is vintage Rolex collecting at its finest, where small details make all the difference.
