There were no dollar coins minted in the U.S. in 1986.
Silver dollars have never been 100% silver. They were usually alloyed with about 10% other metals to give them more resistance to wear. Silver bullion coins issued by the U.S. Mint beginning in 1986 contain .9999 % pure silver.
More information is needed. There are two different one dollar coins that people call "silver dollars" dated 1986. Post new question.
From 1986 to 2010 the U.S. minted over 200 million silver dollars. The mint mark on these can be found on the back side below the Eagle and slightly to the left hand side.
With those dates, the coins are Silver Eagle bullion coins that are made from one ounce of silver and value is whatever the spot price of silver is at time of sale.
It's a common misconception that old silver dollars were called "eagles". "Silver eagles" are modern bullion pieces made since 1986 and sold to collectors and investors. $1 silver coins minted up till 1935 were and still are called silver dollars and were minted for spending in ordinary commerce. Please see the Related Question for more information.
Silver eagles are modern bullion pieces made since 1986 for sale to collectors and investors. Silver dollars from late 1921 to 1935 were used in general circulation. They're called Peace dollars because they were struck to honor the end of WWI. See the Related Question for more information.
Nearly all commemorative silver dollars have been struck in an alloy of 90% silver and 10% copper, the same metal that was used for circulating dollar coins up till 1935. Silver "eagle" dollars issued since 1986 are made of 99.9% silver but these are sold for investment rather than as commemoratives. One of the few exceptions would be Bicentennial dollars dated 1776-1976. Special collector versions were made of clad 40% silver. However these aren't strictly commemoratives either, because the same design was used for circulating copper-nickel versions.
"Silver eagles" are modern bullion coins minted since 1986 and sold to investors and collectors. Their $1 denomination is artificial. The US Mint didn't make any silver dollars in 1929. $1 coins minted up till 1935 contained exactly $1 worth of silver and were simply called "silver dollars", because they were part of normal circulating coinage.
Dimes and quarters minted before 1965, half dollars minted before 1971, and silver dollars minted through 1935. Half-dimes also contain silver, but I wouldn't qualify them as common. Otherwise no circulating US coins contain silver.
None.
No Silver Bullet was created in 1986.