It does not show 3.11 it shows 3.13 Better pictures of both sides and the edge. How about a full picture of the Cent on the scale.. meaning showing the entire scale.
Or it is a 2009 D that escaped from a mint set into circulation. Remember all the mint set cents that year were struck on 95% copper planchets. They would weigh 3.11 grams +/- .13 grams
You could have one of the copper 2009 cents. They were only released in mint sets, but someone could have cracked it out and somehow it got into circulation. Have you tried the drop test?
It looks like a regular Zinc Cent with environmental damage. @DKKamalani if you're absolutely certain your scale is accurate then the only real way to know is to spend the $50+ and submit it to a top tier TPG to have it authenticated. Anything else is just wasting time. BTW: you can check your scale by weighing 4 or 5 cents. Pre 1982 should be 3.11 gms (+/- a few hundredths) and post 1982 should weigh 2.50 grams.