The weight and gold content of the Liberty Half Eagles was specified under the Mint act of January 18, 1837. The composition of the five dollar gold pieces was 90% gold and 10% copper, with a weight of 8.36 grams (129 grains) and a diameter of 22.5 millimeters. The diameter was slightly altered in 1840 to 21.6 millimeters, which would remain the standard until the conclusion of the series in 1908. With the change in diameter, the reeded edge of the coin was also slightly altered, but the difference in minimal and not widely noted.
Production quality of the Liberty Head Half Eagles varies from issue to issue and from mint to mint. Generally speaking, those coins produced at Philadelphia, Denver and San Francisco are better struck than those produced at the other facilities, but this is not always the case. Because a large number of different sources were used for the gold, coloration can vary from sun-yellow to green-yellow or khaki-yellow. Luster also varies from issue to issue, as does the overall eye appeal. In all, this is a very exciting series to study, and a collecting endeavor which can easily last a lifetime.