Bollingen Sandstone

Bollinger Sandstein
Buechberg quarry as seen from Bollingen
Unit of	Buechberg
Lithology
Primary	Sandstone
Location
Coordinates	47°12′N 8°53′E / 47.200°N 8.883°E / 47.200; 8.883
Region	Obersee (Zürichsee), cantons of St. Gallen and Schwyz
Country	Switzerland
Type section
Named for	Bollingen

Bollinger Sandstein or Bollingen Sandstone is a sandstone found on Obersee lake shore, namely between Bollingen and Uznach and Buechberg area, in the cantons of St. Gallen and Schwyz in Switzerland.

The sandstone is found on Obersee (upper Lake Zürich) northeastern shore, namely between Bollingen and Uznach and on the other side of the lake at the Buechberg area, in the Swiss cantons of St. Gallen and Schwyz.

Depending on the layer, the appearance and texture of the natural stone also varies, therefore distinct names have developed at the different mining locations: Güntliweid sandstone means a darker, coarse-grained portion of the deposit. The Buechberg variant has a bit brighter colour, while the Uznaberg sandstone is bright and even fine-grained. In addition to these names, the Bollinger-Lehholz sandstone is mined between Jona and Bollingen.

The Bollingen sandstone is lime bound, it contains 30 to 50% quartz grains and 25 to 35% feldspars, 4 to 8% mica and chlorite, and the proportion of binder lime is between 5 and 18%. The sandstone contains also particles of clay up to 10 millimetres (0.39 in). The color ranges from blue-gray to gray-green, and there are lighter and darker layers.

Since the incidence even partly is mined within the Güntliweid–Bätzimatt nature reserve, Bollinger sandstone is extracted at its different locations usually in the pit mining method, working with wire saws that cut the stone vertically in up to 60 metres (197 ft) deep shafts. Related to Swiss sandstone quarries, the occurrence of natural stone is comparatively large, hence, since centuries the sandstone is mined at several locations.