Calcite has the chemical formula CaCO3 (calcium carbonate) and is one of the most widespread minerals in Slovenia, being a major component of limestone, the most common Slovenian rock.
Calcite can be formed in several ways: by precipitation from cold or warm water solutions, in metamorphic rock, or in the magmatic phase of rock formation. It can also be biogenic in origin. Certain organisms, most notably snails and bivalve molluscs, use tiny crystals of calcite to construct their shells.
Calcite crystals can take on rhombohedral, prismatic, barrel-shaped or scalenohedral forms.
Calcite from Peči pri Kropi na Gorenjskem
Peči is a hill east of Kropa na Gorenjskem. Its elevation is 602 m and it represents an isolated area of karst measuring 0.8 km². So far 49 karst caves have been found on its slopes. This means that the density of cave entrances for Peči reaches a staggering 64 entrances per square kilometre. The deepest cave extends 93 metres deep. In addition to geomorphological and karst attractions, Peči is also known for being the site where at least six endemic species of cave beetles were identified.
A calcite deposit was uncovered in a local quarry which opened in the mid-1970s. At first it was managed by municipal authorities, but later the concession was given to the public company Vodnogospodarsko podjetje Kranj, d.d.
Here calcite crystals can be found along the insides of large cracks or simply in geodes. They measure up to 10 cm in diameter, while the largest clusters can weigh 100 kilograms or more. Rhombohedral crystals prevail. It is evident from the cross-sections that crystal growth was interrupted at several points in time. This caused some of the crystals to grow in the shape reminding us of the Mercedes logo. In addition to rhombohedral crystals, scalenohedral crystals were also found. These are generally smaller and do not exceed 6 cm. There is also some quantity of iron ore, bobovec, which used to be mined in the wider area.