Check the weight. Copper pennies (pre-1982) should weigh 3.11 grams.
1914-D
The 1914 D Penny is a rare and valuable coin. It was minted in Denver and the "D" mintmark is located below the date on the coin. In good condition, it can be worth thousands of dollars to collectors.
Assuming you mean Wheat penny's, the 1909-S V.D.B., 1914-D & 1931-S are the icons of the series.
This goes for all pennies, the blank penny was created in Philedelphia and the penny with the D was created in Denver. If you want to know the material or type you should see "how do you tell the difference between 1982 pennies?"
during the coin making process a pennies where made due to malfunction of machinery. The pennies showed Abraham Lincoln's face twice. These pennies are known as "the kissing Lincoln penny"
Rare dates for Lincoln cents include 1909-S, 1909-S VDB, 1911-S, 1914-D, 1922, and 1931-S. Then some not as rare but still valuable dates are 1910-S, 1912-S, 1914-S, 1915-S, 1922-D, and 1924-D.
The D on a penny indicates it was made at the Denver, Colorado mint
1914 D in perfect, graded condition has a value of $125,000. Most other Wheaties are worth about two cents. Check out the related link below.
The mint mark on the Lincoln cent is under the date on the obverse of the coin, it can only be a "D" or "S" no other mint marks are used.
Explosive 'D' - 1914 was released on: USA: 24 January 1914
Lincoln head 1927 D penny
The value of a 1929 D wheat penny depends upon the condition that the penny is in. A 1929 D wheat penny that is not in good condition is worth about $4.00, a 1929 D penny in pristine mint condition is worth $446.