Coin silver was generally 90% silver, for US coins of that era, IIRC. It got turned into utensils etc. Tableware from Europe was considered better, perhaps in large part because it was made of Sterling. Sterling is 92.5% silver or higher. Brittania silver was 95.83% silver. Eventually, when silver was being mined in quantity in the continent, America shifted over to using Sterling as well.
In all these cases, the balance was predominantly copper though it did not have to be. Copper added hardness as fine silver is pretty soft. The more copper, the harder. Unfortunately the more copper, the easier it tarnishes and the more you have to protect it when heating.
Gerald