June 2024 – greywacke

The mineral of the month was found by the young researcher Greta in the Isar river. However, to be precise, it is not a mineral but it is a rock. The grey colour also gives the name: It is greywacke. Under a magnifying glass, you can see many feldspars. Otherwise, the rock is very fine-grained. Even if the name may not sound so exciting, greywacke has a variety of applications and can be found in many places in our everyday lives. This very resistant rock is used, among other things, as hydraulic engineering rocks, gravel, chippings and as an aggregate for asphalt and concrete. Some sculptures are also made from greywacke. In 2023, a board of trustees under the leadership of the Federal Association of German Geoscientists named greywacke the rock of the year 2023. We would like to thank Greta for bringing us this beautiful piece and wish her all the best for the future and always a handful of rocks in her trouser pocket.           

greywacke

Locality: Isar, Munich, Germany

Size: 3x5x2 cm (HxLxW)

Weight: 180 g