Why would the carbon dating method be useless in dating old coins but not old of adobe bricks?

Carbon dating is effective for organic materials, such as those found in adobe bricks, which may contain plant or animal matter that can be dated. In contrast, coins are typically made from metals like copper, silver, or gold, which do not contain carbon and thus cannot be dated using this method. Additionally, coins may have been minted and circulated over various time periods, complicating their age determination. Therefore, carbon dating is not applicable to coins, but it can provide useful dates for organic components in adobe bricks.