When your gold ring leaves black marks does that mean you are low on iron?

No, if you rub or even swipe the silver ring against your face, and there is a black line left on your face, then you are iron deficient.

If there is no black line on your face, then you are good on iron.

A way to get iron is cooking with a cast iron pan! it's pretty easy to get

Also, girls tend to need more iron than men due to their 'time of the month' where there is a loss of blood. Also vegetarians need to take in more iron. Go vegetarians!