The Dollar
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The dollar coin is the best example of why coin machines shape coin metal. The big Eisenhower dollar (1971–78) was too large and heavy for everyday use and ended up mostly in casinos. Its replacement, the smaller Susan B. Anthony dollar, was so close in size to the quarter that people confused them. When the Mint designed the golden dollar in 2000, it spent 30 months developing a gold-colored manganese-brass skin whose electrical conductivity and weight matched the Susan B. Anthony dollar, so vending machines already set up for the old coin would accept the new one.
Composition & Tolerances
| Variant | Standard Golden Dollar 2000–today |
|---|---|
| Copper | 88.5% |
| Nickel | 2% |
| Manganese | 3.5% |
| Zinc | 6% |
| Structure | Manganese-brass skins (77% copper, 12% zinc, 7% manganese, 4% nickel) over a copper core* |
| Target weight | 8.1 g |
| Weight tolerance | Not published |
| Composition tolerance | Not published |
| Diameter | 26.49 mm |
| Thickness | 2.00 mm |
| Edge | Lettered |
| Magnetic? | No |
| Specific gravity | Not published |
| Conductivity | Tuned to match the Susan B. Anthony dollar* |
| How to spot it | Gold color; same size as the Susan B. Anthony dollar |
Footnotes
Golden Dollar: * The manganese-brass cladding (77% copper, 12% zinc, 7% manganese, 4% nickel) was developed over 30 months so the coin's weight, size, and electromagnetic signature match the Susan B. Anthony dollar, letting vending machines accept both without reprogramming (Copper Development Association).
Sources
- U.S. Mint, Coin Specifications: https://usmint.gov/learn/coin-specifications
- Copper Development Association, The Golden Dollar Coin: https://www.copper.org/publications/newsletters/discover/2000/Ct89/newcoin.php
- SusanBAnthonyDollar.org, Composition and Specifications: https://susanbanthonydollar.org/?p=463
- Wikipedia, Eisenhower dollar: https://en.wikipedia.org/wiki/Eisenhower_dollar
- PGS Gold & Coin, Morgan Dollar Weight and Tolerance: https://pgsgoldandcoin.com/morgan-dollar-weight-tolerance/
- Newman Numismatic Portal, Tolerance: https://nnp.library.wustl.edu/concern/dictionaries/dict516903
- CoinTalk, Coin Specific Gravity (collector chart): https://www.cointalk.com/goto/post?id=2132275
- USPTO, Coinage cladding alloy patent (C71300 conductivity): https://image-ppubs.uspto.gov/dirsearch-public/print/downloadPdf/10513768