002.37.Idrija

Idrija Municipal Museum, Prelovčeva 9, 5280 Idrija

Public

Municipality of Idrija, Mestni trg 1, SI-5280 Idrija

510:IDR;G-950, G-956, G-1013, G-1142, G-1306, G-1396, G-1399, G-1402, G-1403, G-1919.

Ore deposit

The collection contains 10 samples. The native mercury impregnation prevails in them and mould superficial cinnabar layers are subordinated. The samples are in irregular shapes and are differently rich with native mercury. Various rocks are mineralised, namely slate claystone, limestone, slate, siltstone and dolomite. Native mercury is impressed in the rock under pressure, therefore it constantly slowly streams out of the rock in shape of drops. On the other hand, the native mercury at room temperature evaporates by constantly changing the size of the drops. One sample presents the live ore rich with Hg, and in the other specimen we can observe the crystal cinnabar coating.

10 samples of different dimensions

Native mercury (drops), mineralised rocks, minerals.

Mineralisation with native Hg was formed approximately 238 years ago, in the second hydrothermal phase of the Mid-Triassic tectonic period.

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The creation of epigenetic mineralisation with native mercury in Idrija ore deposit is not yet fully explored. It is connected with the second tectonic period at the end of the Ladinian, which was accompanied by great volcanic activity. Due to mercury overflow and lack of sulfur, cinnabar could not be formed, therefore mercury was deposited from Hg vapours. In older lithological parts, Gröden sandstone, Permian dolomite and Scythian and Anisian layers, native mercury in larger quantities only appears in the Scythian oolitic limestones and marl enclosing rock and also in some places in geodes and veins. The extreme quantities of native Hg were accumulated at the Triassic faults and netlike spread veins in carbon slates and Skonca beds. Some native mercury was found in the lowest part of the pyroclasts. The miners named the carbon slates rich with native mercury as slate ore or silver slate.

The described specimens with the native mercury content are being preserved, secured and presented as important natural heritage of mining in Idrija with exceptional universal values. This collection only contains the specimens which were gathered from the Idrija mine and therefore represent the peculiar archive of the Idrija ore deposit, which is globally special. The specimens are a part of the geological collection of the Idrija Municipal Museum. In a lesser degree, visitors can view the described specimens within the permanent museum exhibition “Five Centuries of the Mercury Mine and the Town of Idrija”. The rest of them are stored in the drawers under the display cases, therefore the exhibits can be replaced as needed. They can also be used for different types of mercury heritage promotions.

Idrija ore deposit; samples of carbon slate and Skonca beds with native mercury are from different levels of the upper part of the Idrija ore deposit, oolitic limestones with native mercury are from the lower part of the Idrija pit.

Idrija Municipal Museum, the Geological Collection (showroom 3).

The described specimens are appropriately preserved. The entire geological collection was professionally completed and placed in the renovated premises of the Idrija Municipal Museum in 1992. Therefore, no additional interventions are necessary. Security of the premises is taken care of.

good

Regular seasonal maintenance.

- Inventory Book of the Idrija Municipal Museum.

Mestni muzej Idrija

Miha Kosmač

1. 3. 2018

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