The metal used for the coins circulated in India are as follows(Source: RBI)
Ferritic Stainless Steel has iron at the core of the composition.
Iron is the metal linked to Saturn. Saturn is the planet of Karma and Dharma enforcer. Saturn represents the working class of the society who are comprised of workers, help, laborers, etc. It rewards good actions and punishes the bad ones. Owing to this, the coins are a natural magnet for karma rewards when they are being carried by an individual. Also, their presence can lead to some undue stress in decision making.
Despite this understanding, there is no mortal harm in carrying coins as and when the need be.
Hope this helps