The American Silver Eagle bullion coin was first minted in 1986 as authorized by the Statue of Liberty-Ellis Island Commemorative Coin Act enacted July 9, 1985. The law grants the Secretary of Treasury the authority to mint silver coins containing 1 troy Oz. of .999 fine silver featuring Lady Liberty on the obverse and an eagle on the reverse (see images below).
These so-called "Silver Eagles" are minted in various forms including the "brilliant uncirculated" bullion versions and burnished proof versions. The price and value of the coins is strongly tied to the spot price of silver, but is generally a few dollars higher. The U.S. Mint only sells the bullion version of the coin to outside dealers, but occasionally sells the burnished proof versions until their stock is depleted. Thus, it is often necessary to purchase these coins from an outside dealer rather than directly from the U.S. Mint. Silver Eagle bullion coins can often be purchased singly, in a roll of 20 (below), or in a U.S. Mint sealed "Monster Box" of 500.
The obverse of the Silver Eagle is essentially an enlarged obverse of Adolph A. Weinman's 1916 "Walking Liberty" half dollar design (see a comparison below). The obverse contains the words "Liberty" and "In God we trust" with the minting year at the bottom.
While the obverse of the Silver Eagle is based off of a 1916 design, the design of the reverse is new and shares no resemblance to the reverse of the Walking Liberty half dollar (see below). As mandated by law, the reverse of the Silver Eagle features the words "United States of America", "1 Oz. Fine Silver", "E Pluribus Unum", and "One Dollar".
The following text are the provisions and requirements relevant to the minting of Silver Eagle coins. This text comes from TITLE 31, SUBTITLE IV, CHAPTER 51, SUBCHAPTER II, §5112 of the U.S. Code. Section 5112 also mandates the minting of American Gold Eagle and Gold Buffalo coins.
(e) Notwithstanding any other provision of law, the Secretary shall mint and issue,
in quantities sufficient to meet public demand, coins which--
(1) are 40.6 millimeters in diameter and weigh 31.103 grams;
(2) contain .999 fine silver;
(3) have a design--
(A) symbolic of Liberty on the obverse side; and
(B) of an eagle on the reverse side;
(4) have inscriptions of the year of minting or issuance, and the words "Liberty",
"In God We Trust", "United States of America", "1 Oz. Fine Silver", "E Pluribus Unum",
and "One Dollar"; and
(5) have reeded edges.
(f) Silver Coins.--
(1) Sale price.-- The Secretary shall sell the coins minted under subsection (e) to the public
at a price equal to the market value of the bullion at the time of sale, plus the cost of minting,
marketing, and distributing such coins (including labor, materials, dies, use of machinery,
and promotional and overhead expenses).
(2) Bulk sales.-- The Secretary shall make bulk sales of the coins minted under subsection (e)
at a reasonable discount.
(3) Numismatic items.-- For purposes of section 5132 (a)(1) of this title, all coins minted under
subsection (e) shall be considered to be numismatic items.
Some of my other coin pages:
American Silver Eagles
American Gold Eagles and Gold Buffalos
Morgan Silver Dollars