A 1890-S Morgan Silver Dollar described as "GEM BU" (Gem Brilliant Uncirculated) and "GORGEOUS RAINBOW TONED" is considered special for several reasons:
Gem BU Grade: The term "Gem BU" indicates that the coin is in Gem Brilliant Uncirculated condition. This means that the coin has never circulated and retains its original mint luster. The Gem BU designation suggests a high-quality state of preservation, with minimal wear or contact marks.
Rainbow Toning: The reference to "GORGEOUS RAINBOW TONED" highlights the unique and vibrant toning on the coin's surface. Rainbow toning is a result of the natural oxidation and chemical reactions that occur on the coin's surface over time. Collectors often appreciate rainbow-toned coins for their aesthetic appeal and the various colors that can appear, including blues, purples, greens, and reds.
1890-S Mintmark: The "S" mintmark indicates that the coin was minted at the San Francisco Mint. Mintmarks can add an extra level of significance for collectors, as coins from different mint locations may have variations in minting quality and historical context.
Historical Significance: The 1890-S Morgan Silver Dollar is part of the Morgan Dollar series, minted from 1878 to 1904 and again in 1921. Each coin in the series carries historical significance, reflecting the economic and social conditions of its time.
Collector Appeal: Coins with unique toning, especially rainbow toning, often have increased collector appeal. The beauty and individuality of the toning pattern can make the coin stand out and become a sought-after piece among collectors.
Aesthetics and Eye Appeal: The combination of the Gem BU grade and rainbow toning contributes to the overall aesthetics and eye appeal of the coin. Coins with attractive visual characteristics are often more desirable to collectors.
Market Value: The market value of a coin with these attributes can be influenced by factors such as the overall condition, rarity, and collector demand for coins with unique toning.