1899 O-Mint Morgan Silver Dollar with "Micro O" Mint Mark

The 1899-O Micro O has a very tiny mintmark on the reverse that is much smaller than the mintmarks normally used on Silver Dollars. Speculation is that  the Micro O was a mintmark from a Quarter Dollar.

The Morgan Silver Dollar is the most popular of Americas classic coins.  Minted from 1878-1904 and again in 1921, it is a huge coin that was the favorite silver coin of the Wild West because of its large size and massive amount of pure silver.

The Morgan Silver Dollar is named after its designer, George T. Morgan, who was an engraver with the U.S. Mint in Philadelphia. The obverse portrays Lady Liberty wearing a slaves cap (an ancient symbol of freedom) with the word Liberty inscribed on a ribbon.  The reverse features an American eagle holding both the olive branch of peace and arrows of war.

Due to the massive amounts of silver in each coin, more than 50% of all Morgan Silver Dollars were melted by the U.S. Government in the 1920s to help pay for World War I;   millions more were melted for World War II;  millions more were privately melted in the 1980s when silver reached $50 an ounce; and millions were destroyed or worn out in circulation between 1878 and the 1920s.

This is the largest silver coin ever made for circulation:  it is almost 1-1/2 inches in diameter and it contains over 3/4 ounce of pure silver. The overall silver purity is the standard .900 pure. The reason it is so big is that, by law, it had to contain exactly one dollars worth of silver (the price of silver was fixed at $1.29 an ounce during the era of the Morgan Silver Dollar).