Missouri-themed souvenir ruler and letter opener duo

This object is a metallic souvenir item featuring a circular medallion joined to a flat, straight blade. The user describes it as a letter opener, which is consistent with the general form of the blade portion. The circular top appears to be a commemorative token or coin-style emblem with a raised relief design depicting the St. Louis Gateway Arch and a skyline. It bears several inscriptions: 'MISSOURI 1821', 'SHOW ME STATE', and 'GATEWAY ARCH' in smaller text. The surface of the medallion shows significant multi-colored iridescent toning or patination, ranging from gold and orange to green and blue, which may be a result of chemical treatment or natural aging upon a plated surface. The attached blade features embossed ruler markings on one side, with visible numerals '5' and '6' indicating what appears to be a six-inch measurement scale. The construction is likely a base metal alloy with a silver-tone finish, showing minor wear and surface scratches consistent with use. The piece is stylistically consistent with late 20th-century travel souvenirs. No specific maker's mark is visible in the provided image, so its origin and manufacturer remain unverified.

Based on my visual analysis of the provided image, I have examined this Missouri-themed souvenir letter opener and ruler. The object appears to be a commemorative desk accessory potentially dating from the late 20th century, though I cannot verify its exact age or metal composition without a physical materials test. The medallion feature displays a striking iridescent patination; while this may be natural oxidation, I cannot determine from a photo if this effect was chemically induced to enhance its aesthetic appeal. The piece bears inscriptions consistent with St. Louis regional souvenirs, including the Gateway Arch. I must treat the attribution of this item as a hypothesis, as the lack of a visible maker's mark complicates a formal identification. My estimate is based on general market behavior for common silver-toned base metal souvenirs of this era. Should the item be composed of a precious metal like sterling silver—which I cannot confirm without hallmark verification—the value would increase significantly based on weight. Conversely, if the construction is a simple die-cast alloy with a thin plating, the value remains at the lower end of the travel memorabilia market. A physical inspection to check for stamps, surface wear revealing base metals, and a weight test would be necessary for a more precise valuation. Currently, the market for such items is driven by regional interest and utility rather than high-end collectability. The estimate assumes the item is a standard mass-produced souvenir; if it were a limited edition from a recognized artisan, which is not currently evidenced, the value could be higher.