The 1966 West Germany 5 Mark Proof coin from the “G” mint (Karlsruhe Mint) is a beautiful silver commemorative piece composed of 62.5% pure silver, weighing 11.2 grams with a diameter of 29 mm. The coin was produced in a limited proof mintage of about 3,070 pieces, making it relatively scarce for collectors who favor high-quality strikes with mirror-like finishes.

This coin is often admired for its pleasing aesthetics, and examples with attractive rainbow toning are particularly sought-after. Rainbow toning occurs naturally when silver surfaces interact with the environment, producing vibrant colors that enhance the visual appeal. The colorful toning transforms the coin into a unique collectible with a charming, almost iridescent appearance, elevating it beyond standard untoned specimens.

Proof strikes from 1966 typically exhibit sharp details, fully preserved design elements, and deep reflective surfaces. The obverse shows the denomination and eagle emblem, while the reverse often features historical or symbolic motifs pertinent to West Germany at the time. The “G” mintmark denotes Karlsruhe as the mint location, one of four German mints active during that period.

Collectors prize such coins for their combination of historical interest, silver content, and beautiful finishes. A 1966 West Germany 5 Mark Proof coin with gorgeous rainbow toning is a standout example in many collections, offering both numismatic relevance and an eye-catching visual presentation.

Overall, this coin represents a notable piece of West German numismatic heritage, combining the artistry of 1960s minting with the striking appeal of natural toning effects that highlight its rarity and desirability among collectors.​