Do Postage Stamps Have Unique Identifiers?

This nine-crown stamp from the Czech Republic depicts the zodiacal sign Libra.

It's a little square of paper with perforated edges and strange writing on it. One of the challenges of stamp collecting is how to tell what country and time period the stamp is from. Unique identifiers help collectors identify and properly catalog their stamps.

Dates

The year of issue is often printed in the stamp's margin or incorporated into the design.

Country

The country name appears in its own language and alphabet. For example, Helvetia refers to Switzerland, and EΛΛ'Σ refers to Greece. Some countries identify their stamps with a symbol, such as the thistle for Scotland, rather than by name.

Denomination

Most stamps also display their monetary value in the country's currency. Some U.S. denominations have corresponding letters. For example, "A" means 15 cents. Non-denominated stamps also occur and typically display a postal rate, such as first or second class, rather than a denomination.

Perforations and Watermarks

A standard identifier for stamps is the number of perforations along the edge. Many stamps have watermarks, which become visible when a special solvent is applied. In some cases, perforations or watermarks are the only way to distinguish distinct stamp issues with identical faces.

References

• "The Stamp Collector's Encyclopaedia"; R. J. Sutton; 1966
• "The Official Blackbook Price Guide to United States Postage Stamps 2010, 32nd Edition"; Tom Hudgeons, Jr.; 2009