How Can You Tell if a Coin is Counterfeit or not?

you find out what the coin is made of and lk up what the density of the material is. Then measure the volume of the coin by either measuring the radius of a face, square it, times it by pi and then time that by the depth. Or,if it is a funny shape fill a bucket up to the brim with water, place the coin in the bucket. Measure how much water is left to what was in their before and u will also have the volume. Then weigh it and divide the mass in grams by the colume cm cubed and u will have the density. If it matches the density that it should be then it is real but if it is not then it is a fake