Unusual Coins

For a list of many pure metallic elements and their alloys which have been used in actual circulation coins and for trial experiments.
Coins are popularly used as a sort of two-sided die; in order to choose between two options with a random possibility, one choice will be labeled "heads" and the other "tails", and a coin will be flipped or "tossed" to see whether the heads or tails side comes up on top. A fair coin is defined to have the probability of heads (in the parlance of Bernoulli trials, a "success") of exactly 0.5. Coins are sometimes falsified to make one side weigh more, in order to simulate a fair type of coin which is actually not fair. Such a coin is said to be "weighted".