To the best of my knowledge (and I have been collecting for almost 50 years) only one two-headed US Cent has been authenticated and it is an Indian Head from the 1860's. Search the web for Jakes Marketplace to find two-headed magicians coins. Double headed coins -- novelty items -- are manufactured from normal coins, so they can exist for any year. A lot of them actually have different dates on each side. There are no records anywhere to keep track of which years exist -- it would be impossible to keep track of that, since anybody with a lathe, a grinder, and some glue could make them.
The key to valuation is an accurate assessment of the condition of the coin. Some of the "best" double die cents from 1955 can currently go for as much as $1200 to $1300 depending on the all-important condition.
The United States currently has five different types of pennies: the Lincoln Memorial penny, the Lincoln Bicentennial penny, the Shield penny, the Lincoln Union Shield penny, and the Lincoln Wheat penny.
Centimeter is to meter as a penny is to 1$
The density of a penny is higher.
A penny is a penny. You could try "centidollar" (one hundredth of a dollar). Or in the US: a milliJackson (one thousandth of $10 - Andrew Jackson's portrait is on the $10 bill)
1909
A 1909-S VDB penny!
The rarest British Penny would be the 1954 Penny. There is one known to exist, maybe two, but there could be some doubt about the second.
The rarest and most valuable Lincoln cent that isn't an error is the 1909-S with VDB on it. The rarest and most valuable error Lincoln cent is the 1943 copper penny.
Indian head penny
Indian head penny
Nearly all double-headed coins are fakes. And nearly all 1943 copper cents are fakes. Combine the two and it sounds to me like you don't have a real coin.
If you refer to general circulation Australian Pennies rather than Proof coins, the order runs something like this - 1. 1930 Penny is the rarest 2. 1920 Penny with no dots on the reverse 3. 1925 Penny 4. 1946 Penny
Only the Philadelphia mint made pennies in 1900. There isn't really a rarest.
1909 s vbd
The Canadian "double-headed" cent is equal to the British One Penny. The Canadian one "cent" is equal to the British 1/2 penny (so a British penny is 2 cents or 1 double-headed cent). When first issued, the Canadian government had them struck to a standard of 100 coins to the pound of bronze rather than the the British standard of 80 coins to the pound of bronze. The first 1858 issues, however, were unpopular and originally had to be sold at a discount. It is believed the Canadians joined the two cents together to make them equivalent to the British Penny.
This is a novelty coin not made by the US mint and has no collectible value.