Agates of the Kaczawskie Mountains
The Kaczawskie Mountains, located in the northern part of the Sudety Mountains, form one large geological unit called the Kaczawa metamorphic. The geological structure of the region has a two-storey character. The lower storey is made up of various, weakly metamorphosed sedimentary and magmatic rocks. These formed from the Cambrian to Lower Carboniferous period (570-330 Ma).
The upper floor is built up by unmetamorphosed or weakly altered sedimentary and magmatic rocks formed between the Upper Carboniferous and Upper Cretaceous (330-65 Ma). Agate occurrences are associated with volcanic rocks of the Variscan orogeny (Carboniferous/Permian).
NOWY KOŚCIÓŁ AND SOKOŁOWIEC
South of this location, agates are found in quartz riolites and their tuffs. They form so-called “agate boules”, the mechanism of whose formation is not clearly defined. Agate occurrences also have their common names. Among the most well-known are “Wrzynka” (since the 19th century), “Piekiełko”, “Skrzyżowanie” or “Aleja”. The agates from these appearances differ slightly, but savvy collectors can tell which place they come from. When cut, they may have a “star-shaped” or “atoll” pattern, or they may show parallel layering (the so-called “Uruguay type”). The agate boules also contain druses of different-coloured quartz varieties. In Sokołowiec, on the Owczarnia hill, agates with a characteristic dark colour were found, as well as unique agates of the so-called “Paraiba type”.
GOZDNO
Agates occur here in fields to the west of the village. They are encountered in large porphyry boules and therefore only fragments of them are excavated in the form of veins, lenses or layers. Brushes of quartz crystals of various colours, as well as pseudomorphoses and perimorphoses after carbonate crystals (most probably calcite) are found quite frequently.
RÓŻANA
Agates are found at the foot of and above the quarry located on the south-eastern slope of the Ox Hill. They occur in the form of almonds in Lower Permian melaphyres, which petrologically are referred to as trachybasalts. In addition to agates, various coloured varieties of quartz, calcite, barite, iron and manganese oxides, zeolites and chlorites are found in the almonds. An interesting feature of agates from Różana is their luminescence under ultraviolet light.
LUBIECHOWA
Agates are found in a small disused quarry. They are found in almond-shaped Permian melaphyres. In addition to agates, geodes may be filled with coloured quartz, calcite, baryti zeolites.
PRZEŹDZIEDZA
In a disused quarry near this village, melaphyrs were mined. In their crevices, agates and jasperoids with a characteristic vein-like structure are found.
PŁÓCZKI GÓRNE
Agates occur here in Lower Permian melaphyres, which were formed by surface lava flows. It is between 50 and 200 metres thick. In the morphology of the area, it is marked by gentle hills (Pleban, Mogiła, Wieżysko and Lipień). The agates of Płóczki Górne are exceptionally diverse in terms of types of drawings and patterns, as well as colours. This makes them a favourite object of agate collectors from the country and all over the world. In addition to other varieties of quartz, green – extremely rare prasiolite – can also be found here.
