The U.S. market crash that began on September 24, 1869, after Jay Gould and James Fisk tried to corner gold was called Black Friday.
Gould and Fisk sought to drive up the price of gold while limiting the amount available for sale. Their scheme depended partly on influence and inside access connected with the Grant administration. When the U.S. Treasury intervened by selling gold, the price plunged, ruining many speculators and disrupting financial markets.
The episode is also known as the Fisk-Gould scandal. It was not the same event as the later Panic of 1873, which began after the failure of Jay Cooke & Company. The word “Black” in Black Friday described the financial disaster, decades before the modern shopping meaning became common.