Assuming you found it in circulation, at most 2 cents depending on how worn it is.
They were steel, not silver.
No. No genuine US coin other than the 1943 steel penny will stick to a magnet. If you have a US coin that sticks to a magnet other than the steel penny, it is a counterfeit.
If it sticks to a magnet then it is not copper. If it does not stick to a magnet then take it to a collector to be evaluated. It could be worth a lot of money.
Your "black" penny is most likely a 1943 steel penny. (Check it with a magnet. If it sticks its steel) It is worth about .10 - .20 cents.
Try the magnet test, if it sticks to it, it's steel.
Put it under a magnet. If it sticks it is a steel penny. If it does not stick take to a collector or professional who can examine it further and give you a answer.
A normal 1979 penny will not stick to a magnet -- it's made almost entirely of copper -- a non-magnetic material. So for your coin to stick to a magnet, it has to either be fake, or plated with some kind of magnetic material. In either case, it's value would only be as a novelty item -- perhaps a couple dollars at best.
If genuine, they are worth tens of thousands of dollars. Certification is required.However, 99.9% of them out there are fakes. Try checking it with a magnet -- if it sticks, it's a fake.1943 copper penny? Value (US$): $200000
A magnet will pick up a penny because Josiah is gay
Unless it's a proof coin, 1¢ Note that this site has a Coins and Currency thread for asking questions about, well, coins and currency. Money and Credit is for things like checks, credit cards, loans, etc.