This coin is an 1866 Seated Liberty Quarter, a notable piece from the United States coinage series. Struck at the Philadelphia mint, it features the iconic Seated Liberty design, symbolizing freedom and liberty. This particular coin is a proof version, which means it was specifically made for collectors and not for general circulation. With a denomination of 25 cents (a quarter), it is crafted from silver and weighs approximately 6.22 grams. The coin has a diameter of about 24.3 millimeters, making it a compact yet significant item for numismatic enthusiasts. The mint mark is absent, indicating its Philadelphia origin, as this mint did not use mint marks for coins produced before 1900. The 1866 Seated Liberty Quarter had a limited mintage of just 725 pieces, making it a rare find in the numismatic market today. Given its exceptional quality as a proof coin, it is highly sought after by collectors and holds considerable value. This piece not only represents a slice of American history but also showcases the artistry and craftsmanship of coin production during the 19th century.