According to Michael P. Lantz of Lakewood, Colorado, a former employee at the Denver Mint, approximately ten 1974-D One Cent pieces were made in Aluminum: "I personally didn't make any of the Denver aluminum cents, I was on the graveyard shift when they were stamped. A friend of mine, Ernie Martinez, die setter and later general foreman, stamped the aluminum cents on one of the Denver Mint's standard presses. When I talked to him last Sunday he told me that he stamped around 10 of them. One thing he recalled about them was that they 'finned' badly. After stamping the blanks he returned the finished aluminum cents to Harry Bobay, general foreman, who took them to the coining division office where they were shipped back to Mint headquarters in Washington, D.C. From there, who knows what happened to them."

unfortionatly that coin isnt aluminum since aluminum has a different color and is lighter..and after a long time aluminum coins tarnish or are hard to read.

here is some info about the 1974-d one cent from www.coinfacts.com :-

Mintage:
Circulation strikes: 4,235,098,000 that means that 4,235,098,000 were made...making it very common.

Metal content:
Copper - 95%
Tin and Zinc - 5%

and a note quoted from coinfacts which has info about the aluminum coin also :-
so it is very unlikely that out of the 4.2 billion cents made that year that you got one of the aluminum ones which only 10 existed

Actually, I think around 500 PHILADELPHIA coins were minted to show the members of Congress. Those are the ones that may have leaked into circulation or into a collection even though most were given back to the mint.

im talking about the denver mint not phily and in coinfacts it says only 10 aluminum 1974 denver cents were made

Yeah, I stopped for a second when I read that but I saw the cent you posted was a 1974. I was going to scroll to the top to see if the cent he posted was a D or a P but I was too lazy

I stand corrected, RD! You've gotten me twice today.