Golden Penny

[Tuckerfan]

I found a gold colored 2000 US penny last night, and I'm kind of curious as to how it got that way. I scratched the surface of the penny and got the zinc center of the penny, no copper at all. Perhaps this got mixed in with a batch of Sackies? Anybody know?

[Duck Duck Goose]

I found a way to make your own "gold pennies", FWIW.

http://www.loupcity.k12.ne.us/academic/project2.html
[list of ingredients]...

1. Mix together 3 grams of sodium chloride and 15 mL of vinegar in a clean, 100-mL beaker.

2. To clean the copper pennies, place them in the sodium chloride/vinegar solution until they are shiny.

3. Remove the pennies and rinse them thoroughly with water. Dry with a towel. Do not handle the clean pennies with your hands. The oils from your skin can interfere with the reaction.

4. Mix together 1 gram of zinc, granular, and 25-mL of 3 M sodium hydroxide solution in a clean evaporating dish. Chemical splash goggles must be worn.

5. Using a hot plate, carefully and gently heat the mixture to steaming. Do not allow the solution to boil or splatter.

6. Using tongs, immerse the penny in the mixture until it is completely coated with "silver."

7. Use tongs to remove the penny. CAUTION: the penny will be very hot. Carefully dip the penny into a beaker of distilled water. Shine with a towel. The penny should now appear silver.

8. Using tongs, heat the penny in a burner flame until the penny turns gold. Immediately dip the penny into a fresh breaker of distilled water. The penny will be extremely hot and should be handled with tongs until it has cooled for several minutes. Students will enjoy showing their friends their "gold" pennies.

...[followed by list of "do not try this at home" safety disclaimers]Could that be it?

Better Living Through Chemistry. :D

[Duck Duck Goose]

Also, I note that it specifies copper pennies dated 1982 or earlier, so what's the date on the one you've got?

[Duck Duck Goose]

Oh, duh. 2000.

Bring more coffee...

:D

[Lumpy]

I've seen pennies that were metallic green, blue, and red in addition to gold. Someone out there is anodizing pennies for some reason.

[psychomonkey]

Its an old trick done in science classes. Essentially you coat them in zinc, and thenheat the zinc, so that it either tarnishes orbonds with the copper to form rass. I dont recall the specifics. I do recall that when scratched, the sinc (silver) shows through though.

[samclem]

Most likely, if you find a gold-colored cent-nickel-dime-quarter-half these days in the US, it was gold plated by a promotional company that then packages them and sells them to the public for outrageous prices. We get to purchase them in our coin shop years after the fact. There has never been a US coin type made in the last 100 years that I haven't bought gold-plated.

Directions: take a cent, plate it with gold. Total cost=5 cents. Package in a fancy holder. Cost 10cents. Sell for $9.95.