In the 1930s it happened
to gold coins such as the United States’
Eagle and Double Eagle when the demise
of the gold standard in 1933 meant they no longer circulated as common currency.
Demonetize/Demonetization
In the broadest sense, the
withdrawal of coins or notes from use as money, depriving them of standard monetary
value. In precious metals, this happened
to many silver coins in the 1870s when European nations switched from a silver
to a gold standard.