Discovery of mercury and rich cinnabar ore
According to legend, mercury was discovered in Idrija in around 1490 by a tubmaker as he was soaking a wooden bucket in the stream. An unknown, glittery substance found its way into his bucket, and this substance turned out to be mercury. Today, the Church of the Holy Trinity stands on the spot where the tubmaker made the discovery.
In the first ten years, miners carried out their digging in poorly mineralised shale. Convinced that there was no more ore to be found and that the ore deposit was depleted, Idrija miners and the mine administrator began to fear that the mine would have to be closed down. On St. Achacius’ Day, 22 June 1508, Idrija miners experienced the second great historical discovery. While they were deepening a shaft along the Nikova Stream, which was later named Achacius’ Shaft (due to the date of the discovery), Shaft of Good Luck, they came across highly mineralised cinnabar in the Skonca beds at a depth of around 48 metres. This discovery laid the foundations for the following five hundred years of mining. To commemorate this important event, Idrija miners celebrate their own holiday, and have selected St. Achacius as their patron. For several years, they ceremoniously celebrated this holiday with a holy mass and procession, but nowadays 22 June is the holiday of the municipality of Idrija.