Chocolate can contain a wide range of vitamins, minerals and antioxidants. But not all of them naturally occur in chocolate. Some vitamins and minerals may be fortified. It depends on chocolate producer what vitamins and minerals are added.
Dark chocolate is made from cocoa, which naturally contains iron, zinc, copper, selenium, magnesium, phosphorus, manganese, potassium and polyphenols (antioxidants).
The total amount of minerals and antioxidants in chocolate depends on how much cocoa does it contain. Chocolates you can buy in a shop usually contain between 20% and 90% of cocoa. Milk chocolate usually contains less cocoa, while dark chocolate is characterised by higher cocoa amounts.