According to London Bullion Market Assn. the largest one day drop in gold was $112 on 22nd Jan 1980, the day after the $850 peak, representing a 13.2 % drop.
The next highest drop was 28th Feb 1983 with a drop of $56.25, representing 12.1%.
After that there were quite a few drops in the $30 to $40 range though most were in 1980.
Cheers
Andrew
