4.18 Grams .900 gold and .100 copper (21.6 ct) is the composition of this vintage 1878 S gold piece. 2 1/2 Dollar denomination it is 18mm in diameter, or 1/10th mm larger than a modern Roosevelt Dime. Not perfect, a light scratch in her hair towards K1 and a few small marks but all around a decent piece. May have been used in jewelry.