Gold, being more "desirable" can account for some level of deviation, but not to levels like 60-80x.

It used to be around 17-18x when gold and silver were used in coins.

I remember the 5 francs was 25gr silver x 0.9 purity = 4.5pure grams silver per franc.

The 20 franc gold coin was 6.45gr gold x 0.9 purity = 0.29gr gold per franc.

So it was 4.5grams of silver per franc / 0.29grams of gold per franc = around 15.5x... That was in the ~1860s.

So it should be around 20x tops.